It's good to know some other games used it before. I say, learn from it: let's implement here what didn't work there.
Besides, it's not yet that crowded here. Although there should be made some "rules" (or whatever) about combining it with multiple characters. We could just let guild be able to buy such things.
and Donari: I know guildhouses already exist, we share one. But the present guildhouses are not suiteble for shops.
And when one shouts "i sell" at the auction, you can't see where you should buy, it's not consistent enough for a fundamental economy.
*edit*
You mean, like, a giant inflatable potion bottle? Or chair? Or axe? Or something like that?
Yes, precisely. Like a giant infloateble item. I actually don't know if it's possible to make something like it, but hey, it's an idea.