So here's one idea, shared with me by Braila of Thunderhorn (our guild's tree-mendous healing druid) during last weekend's Karazhan run: How about a trinket chain?
It makes a lot of sense. Blizzard implemented a keychain to get keys out of our inventories, and considering that we're all hauling around tons of trinkets lately (I had seven on me, and one of our warriors had eight with him), this seems like the first place Blizzard should go to thin out the inventory. It's not like trinkets are huge items-- why should they take up 1/16 of Netherweave Bags when you can fit 200 arrows in the same place? Spare trinkets should have their own tab to sit in, something that grows the more you get, just like the keychain.
Of course the obvious solution would be to just not carry so many trinkets around. But there's so many of them for every situation-- healing, solo grinding, raid healing, DPS, PvP-- that it's no wonder everyone at 70 has such a collection. Blizz should give us a chain to put them on.