I dealt with that issue when we were moving offices. I had my fish in a cooler for a few hours while I was waiting for the movers to build my desk & furniture, so I ran my AC's on the cooler to keep the BB going. They were pretty noisy because the angle of the intake tube was all wonky (thick cooler wall), but they worked...
Only thing I can think of for you is switching up to a AC110 thats made for that thickness of lip. At least you could transfer the old media over that way. Otherwise, you would have to go with a canister or something. I wouldn't be cutting/shaving the lip of my tank, but thats just me.