I am not convinced there has to be a slippery slope argument. To my knowledge no one here is/arguing in favor of more magical items being released into the game. What I hear, or maybe the parts I am listening too, are concerns about how stuff (magical items) gets released into the game.

By my reckoning there are 5 modules in the campaign where you can walk away with a permanent magic item. In two of them you explore/loot an unknown ancient place ... and in the other three you kill "people" and take their stuff. Two of these mods basically make sure everyone gets something. There was also the Vault special event which had a handful of magical items and access to limited runes.

The opportunities, as intended, are rare. And people can miss stuff (by playing the wrong character, losing a roll off, not being able to make it to a special event ... whatever). And its possible you're playing an unusual concept and you'll never see the cool item that would be your "signature item."

So for me the question is: are there other ways to distribute magic items through out the campaign?

I don't know that we need a Marketplace. Or Signature points. But I also don't want rest on any laurels thinking that things are perfect as is. As far as stories go, "I found some ruins no one has ever heard of" or "I killed some people and took their stuff" is not necessarily great theater. Maybe we do want to consider

It seems to me that there should be other models. One possibility is the "Elebac" model where over several encounters in mods the NPC makes you something. A varrient of this is what I call the "deep pockets" model where and organization (country, mother church, emerald society) ultimately reward's you with something from their vaults.
Both of these are maybe part of a bigger story. And maybe give some control of what gets produced to the player.

Surely a bunch of creative people like us can think of other story driven ideas as well.

I am beginning to agree with Henry's reluctance to this idea. There is a lot of discussion of gaining access to things that don't make sense.
Weapons, Armor, Shields, Special Material. (I'm talking about building your own.)
The old campaign was filled with certs that either granted you an item of your choice made from special material (Arms from Tir Betoq), or granted you access to special material and you paid for the item itself (Mithral Item from Solanos Mor, Favor from Colonel Ankim val'Abebi.) Every player at the table got one.
The Crusade Arc has granted this type of reward 4 times, and I see no reason that this will stop. I have someone at the my table that gets excited every time the dwarves at in a module because she expects this type of reward. This reward was on both the CP and VCP for all 4 modules. RCP haven't been created for any of these modules. SO that's be something to clarify.
For upgrades I can recall 4 certs that upgraded your items in the old campaign, 1 from the Sand Apophics, 1 from the Altharians, and 2 from Elebac and the last one from Elebac went right to the best you could have. Everyone who had the lower item got the higher, and the final Elebac upgrade went to everyone.
This has been used by the staff before I don't see why they won't use it again. In their own time.

So again I see no need to ask for making weapons, armors, shield or gaining access to special items. Or to upgrade items. We want them but we have to patient.

There is no need to discuss runes because they can be bought, sold, and traded among your items. While they are magical they are not "magical items." Any runes missed in modules can now be bought. While there are 2 types of runes that can't be bought. They are also not showing up as loot in modules released to the public, so no one is getting them over others. We may want them now but we can wait until they are released.

The real issue is magical items. PCI has created 2 book filled with these items FiM pg12-31 and FiM2 pg14-43. These can't be bought, this are being released in modules, people are getting them over other people, and players have complained.
We are not talking about handing them out in more modules. We are not talking about crafting new ones to better suit us. We are trying to find a way to distribute them so players can enjoy receiving them, but without just adding "Ye Olde Magic Shoppe."
I agree that purchasing them from a Marketplace is a bad idea.
I think making them sell for 0Gc is a bad idea in the long run.
I think this SP (or whatever) could still work if people are willing to let go of runes, weapons, armor, shields, and special materials.
SamhainIA had a nice idea about using favors. Instead of a writer having to make magical items. They can include a favor from our patron. Of course it has to make sense, Like a favor from a Sanctorum Mage could give access to a Tier 1 Wand, or a favor from a church member could give access to any 1 Tier 1, or Tier 2 Elixer, Oil or Potion.
I like favors that are used, I never enjoyed in the old campaign the ones that state "It may have future use" because it creates pages and pages of favors that people don't use, and don't cash in, because "just in case in comes back". I like the new ones, you can use this favor for this or that. And besides everyone gets one.
Tony said earlier that's it's easier to write more items in when you are dealing with certain situations like a lost fortress, or an enemy base, or a large group of powerful enemies.

1 final reminder. We don't need to make it complicated because the items already exist, the rewards are already distributed, we just need to meet in the middle. I just gave 5 examples; 1 Sanctorum Mage favor, 1 High ranking Priest favor, 1 Lost Fortress, 1 Enemy Base, and 1 large group of powerful enemies. That could take us through an entire Tier of magical items and then some. We got 4 modules in the Crusade Arc that granted magical items. 2 of them caused disagreements. If the numbers stayed the same 3-4 modules per Arc and we could find a solution, that's more than the SP idea generated (1 item per Tier).

YES. This!

I completely agree that favors without a use are frustrating. I would add useless fame is also frustrating. Sometimes it is unclear how broad Fame is (but that's a separate issue from this discussion).

Some of the newer favors are very useful (2Gc), some are very situational (get out of canceri jail), and others are of highly questionable value (treated fairly and in good favor by a particular family).

As to non-magic items, as of yet, I don't think there's been any possibility to gain exceptional armor (other than buy it which is impossible for heavy or some medium armors). The non-buyable runs have been given out once (vault at ArcaniCon this year).

Favors without use is precisely why, in the previous campaign, Sean and I put in the system that gave *every* favor a use. If players chose to hoard obscure favors... well, that is likely to continue regardless.

The concept of stacking favors is also likely to continue.