Can I tell you how much I hate pyramid schemes and chain letters? Since this is actually an interesting idea, it's the only reason I'm in on it.
Kees (who has a pretty sweet first name in my opinion), one of my buddies from the Inkscape project posted an entry on his blog about an "art pyramid scheme". He also recommends using the Creative Commons Share-Alike license which I'm not going to push on people here, but will be doing so myself.
So... as with his. If you're one of the first 5 people who comment on this post, I'll create an original piece of art for you, but only if you promise to offer the same deal in your own DA Journal (as it's such a fitting place).
By the way, there is no guaranteed time-frame for said pieces, and no obligation on my end for it to be very detailed.