We have one that we built using a triple oak about 12' up. Made a ladder out of 2x4s and built the platform like a little deck. Then put railing on it, added a strap on tree seat, painted it grey primer to match the oaks and will hang some blind material on it soon. (Ran tight on budget) We took 2 deer out if it this season and saw dozens more!
We have another that is a pallet sitting on a 2 x 4 frame with two front leggs 8' tall from 4 x 4s and bolted to a double tree. This year during the off season we will replace the pallet with decking. It also has rails and blind material backed by lattus on it and we have shot a bunch out of it as well. You really don't need to get real high to have a great deer stand.