depending on what type of style or stand you're looking for and height. 3M makes monitor stands that are somewhat height adjustable, or IKEA has stuff you can assemble into a display stand as well.
Try the Ikea hacks with the end tables. Works great unles you have to keep adjusting. I did the thing where you bolt a shelf onto its legs for the keyword. Works really well. And this way I can use earthquake putty to secure the iMac. It's a bit hefty, so I want it secured down as solidly as possible.