I'm not talking about recluses like Axl Rose and Sly Stone, who have issues unrelated to financing which keep them from releasing product. I'm thinking more about someone like Ernie Isley or, yes, Àngela Winbush - people who presumably wouldn't be averse to hitting the studio if they could be assured in advance that they would get back their costs and (ideally) a bit extra.
I'd picture it working somewhat like an eBay auction (remember eBay? It's where you used to go for rare LPs before they all starting turning up on Rapidshare). Anyone interested could sign up for a central clearinghouse where you could put down money toward a new album by a given artist, who might or might not be amenable - it would be up to the artist to indicate interest, specify a minimum bid, etc. Everyone going to the site could see how much money had been pledged toward each artist - you could track fastest movers, newest additions, largest budgets, and so on.
The money would be placed in revocable escrow, so that you'd really need to put up the dough but you could get it back if you got tired of waiting for that next Leo Sayer disc - this would address the hypothetical problem where an artist could have an incentive to wait indefinitely, letting the budget go up and up, rather than actually making the record. Once the artist said yes, got the cash and recorded the CD, everyone who fronted money would get some freebie, like an autographed copy. (Sobule made an elaborate system with various levels, so that if you contributed enough you could even sing a duet on the record, but I doubt many artists would be that flexible.)
To really build a system like that you'd need someone to hold the money, and I'm certainly not volunteering. Thanks to the financial crisis nobody's making any interest to speak of anyway, so the only thing you'd need to worry about would be someone running off with all the money. But we're all music fans, we can trust each other, right? Right? Did I just lose everybody? Anyway, assuming the practical part can be straightened out if there's enough interest, let me throw out my price list: