Pretty soon you might be able to apply for a loan before buying a coffee and doughnuts -- under the same roof. Citizens Bank just opened a pretty-full-service branch in a Dunkin' Donuts store in Bellingham, MA.The unit has three teller windows, an ATM and is open seven days a week. According to a Dunkin' spokesperson, this store is only a test and no more are planned in the near future.Is this one of those crazy win-win scenarios?Of course, Dunkin' will get some favorable foot traffic from the bank. It's not exactly easy to find an in-person teller to help you out on a Sunday, and someone who's just deposited a check might not feel so bad splurging on a latte.The bank gets the benefit of being located in an outlet where millions of Americans go daily to fuel up. The question is whether non-Citizen customers will switch accounts or open a new one at the branch. If not, maybe then it's just like placing a very expensive ATM in a fast-food outlet?