I don't really have a "chief" thread to link to - perhaps
this one would do - but there have been several discussions about the inherent challenges of loaning Bitcoins, most of which boil down to "how can you have a system of trust when transactions are anonymous?" Have you chosen a strategy to deal with this? Or would it be less of an issue with credit unions for some reason? (To be honest, my understanding of CUs vs. banks is a rusty.)
The issue of maintaining anonymity while still being somewhat fraud and theft resistant is one I've wrestled with and I'm not really sure there's a way around it. If you're anonymous, there's no way to verify your identity or to find you if you skip off with the Bitcoins. Even charging a membership fee like most CU's do doesn't assure anything except you'll have the membership fee if they skip off. Not really valuable if they take 50,000btc or something.
It's going to take some thinking but there has to be a way around it.
Anthony