Making box blinds for on the ground or up in the air is very easy to do. A simple google or even a search on this site should get you some good ideas. It's really as simple as buying some good plywood, doing the proper measurements for the windows, etc. and doing it. The corners and top can all be screwed together by using 2x2s. I'll find a couple pictures of one I did from the start using the 2x2s and it finished and assembled out in the swamp with steel covering the wood and painted to match the foliage. The windows are real glass hinged to drop down so it's easy and quiet to open them and not have to use anything to hold them open like you would need to do if they lifted. If you are going up in the air with one like you are mentioning, you'll need to anchor the sections together and then really anchor it at the corners down into the ground with some heavy cables to keep it in place, especially in an area where you get plenty of wind like you probably do in OK. Put carpet on the floor and with it anchored solid it should do the job for you.