Interesting idea. I think the gents above me covered the main problems already, but I'll be interested to see where you go from here.

From a technical pov, I wonder what implementing something like this'd do to your load, if you want to keep circulation going. You'd have to start out with a whole bunch of stuff, especially if you don't throw alts out of the window straight away. Item decay would be a must as well I suppose, you can't simply rely on money sinks as they'll, you know, just get the money out.

Would be an interesting experiment in current day player end-game tolerance though.