Can you wear tenis shoes all the time? I know part of the issue with my old desk was it was required I look nice for some meetings (and wore "nice" shoes with wooden heels) or sandals because the room had a stupid cooling system (and the dev area was almost 80F).
Both of those cut down on the time I could handle standing.
My standing desk is just a normal desk put on top of cinder blocks so my drawers and surface are all setup for standing.