Convincing a traditional bank to fund your bitcoin business really isn't going to happen, not necessarily because its a bad business idea, but because bitcoin is an unexplored minefield and no bank wants to be the guy out there exploring it first.
It's pretty easy to get unsecured credit for a bitcoin business. The APR is in the 20s, but it beats the average bitcoin loan which is in the 200-400% APR range. As far as I can tell, these microloans are for people who want to buy something right now and thus don't want to wait for their money to clear through dwolla/gox or are short a little on a purchase and can mine the difference in a week or so. There doesn't seem to be an appetite for large loans both on the borrowing side because the APRs are too high and on the lending side because the risk of default is too high.