Substitute "walking" for "standing" and all these troubles go away. I have walked many 8 hour shifts with only a lunch break in between. A walking desk is not much more difficult to make. Get a treadmill from Craigslist and then find a bookshelf to put the monitor on. Or stack some boxes on a desk and put the monitor on top at eye level. Or you could even attach the monitor to the wall with an inexpensive wall mount.