I like the idea. If you pulled this well it would off load many coin devs with the bounties.
I would suggest having some custom themed web pages for different coins (or ability to custom theme them to their liking). Having it unvaried could emotionally detach coin users from the coin they support.
I can imagine people really quickly becoming promo-bots.
Overall I can see some bussiness there.
Great ideas on offering that sort of bounties and allowing those placing them to have themed pages.
Really, really, really great idea as a matter of fact!
We've been playing around with a lot of ideas the past week on different things we want to try. The plan is to offer a closed beta in the near future.