You can also forgo the buckle on the inside and use velcro with an adhesive back. Once the belt is folded over the buckle and the keeper cinched up to the fold the belt should hold itself fairly snuggly in place. The velcro would only be needed to keep the loose end from dropping out from under the belt or creeping up over the belt.

You can also substitute the stitching for rivets. They're just a little faster than stitching.