Okay so probably the easiest will be just building boxes with butt joints. Use a good waterproof glue, and lots of screws, make sure you pre-drill pilot holes though first. If you can afford a wood that can handle moisture well that would be preferable. Then as I said earlier concentrate on getting good waterproof coating. If you chat to other beekeepers, ask if there is not someone locally who can give your hives a wax dip in paraffin wax. It will safeguard your bees in case any of those old hives had AFB, and it makes the wood basically impenetrable by water.

Yellow Jackets are a pain, I'm also trying to find a nest near our apiary.

BTW, have you visited Beesource.com - Beekeeping resources for beekeepers since 1997!. It's the largest beekeeping forum on the internet, and extremely helpful.