i'd rather see people adopting very small modules. possibly people could bid on them based on the module elegance and usefulness and extensibility, etc. lines of code can get removed, whereas concepts tend to stick around, plus motivating well designed modules is better than motivating greater number of loc.
every month that goes by without a bug, the module slightly increases in value, or the donator gets paid a dividend.
I absolutely love your idea. I think the best thing about it is that it can be dead-simple or ridiculously complex, with dividends and whatnot, but the idea works for so many projects.
An added thought could be sponsoring modules that don't exist yet to spur on their development, maybe your company uses some open source product that supports a bunch of file formats but not .xyz, you could donate to a speculative XYZ Module and then everyone benefits and the developers have an incentive to write it.
Yes, I'd much rather adopt a function... although I'd rather not pay more than $5 a month.
Perhaps a function could be adopted by more than one person? First two people get to be parents, then after that your title would be grandparent, aunt, uncle, cousin, and what have you.
every month that goes by without a bug, the module slightly increases in value, or the donator gets paid a dividend.