To stack or not to stack - limited space for amps

I want to bi-amp with two class D SS amps. Space (shelving) is limited. I assume that it is not advisable to stack amps. However, with the amps being class D, the heat factor shouldn't be much of an issue. I was more concerned with other negative aspects?? I was considering placing one on top of the other with some form of after-market damping control (i.e.: "feet"). How bad of an idea is this? If it is doable, what type of damping product would be best utilized.

I think stacking Class D amps should not be a problem.
You should be able to hear a hum from the speakers if there is a problem with magnetic fields caused by the electronics. I can't stack anything without causing hum from the transformers picking up the field. Six inches away, and no hum.

Jim S.
The only problems this could cause would be cosmetic. Little rubber feet can leave permanent marks on the top of the lower amp.
Other potential problem lies in the fact that some speaker cables weigh more than certain Class D amps.
Don't laugh but some of my gear (Innersound) is advised by mfg that it is okay to stack (my preamp and phono stage), which I do. Some gear, mfg's advise not to stack, so suggest contact them. Now, as for isolation devices (after market feet, i.e., walker valid points, cera pucs, symposium fat pads, thier properties are greatly affected by stacking. Basicaly, you can lose the benefit from having feet under the bottom component, by placing a compoent above it. I have spoken to a few manufacturers about this. Putting feet under each component that you stack would give a different effect as opposed to putting feet under each component, without stacking. It may or may not be an imporvement, but definately not (necessarily)the desired effect of the designer.
Thanks for the thoughtful advice. I checked with the good folks at PS Audio, who recommend against stacking because of potential RF interference between the two amps. They recommended at least eight inches apart.
DarnÂ….the wife won't like it when I bring out the old rack.
Why don't you try it first?

I've not had any problems stacking class d equipment of the same and different brands.