Hardware is the problem is you want the figures on your keys to match what they do. (I love such "tiny" details).
In the past I did try various kind of stickers, since it was hard to find my preferred qwerty layout (canadien normalise), but they were just a nuisance.
So I changed to a apple canadian qwerty layout (not many differences), it's just perfect - hardware support and software support out of the box.
And whenever I get a us qwerty I can still be efficient.
Software, on the other hand, is a slight annoyance. Colemak (and any other keyboard layout) can easily be available in pretty much any OS except iOS. Also, many games implement their own keyboard input handling, and disregards custom layouts.