I don't see what the practicality of building an adjustable stand is. I mean I understand the benefits of it, but the time, energy, and supplies put into it is more than I'm willing to spend.
My hive stand right now involves 2x4's and cinder blocks. Anything more than this to me is pointless, as my number of hives increases and decreases, and moving them around the yard becomes necessary from time to time, building a permanent stand of any kind becomes more problematic than building more hive boxes, or frames.
If you are concerned about getting into smaller hives without bending over, why not just put a few extra cinderblocks under the small ones. As it grows, take out two cinderblocks as needed.