Once you get up to 36" small pieces of furniture (little shelf units, or big CD stands, or those tapered "lots of plants" stands sometimes work better.

Otherwise, good 'ol "racks and stands" has a good selection :

http://www.racksandstands.com

Do a "superbrowse" search for stands >30" high.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8