I tried Dvorak for a little bit. I started to pick it up, but it's impossible to maintain Dvorak and QWERTY at the same time, so you really need to persist on every machine you touch. I work on lots of shared machines (through KVM or remote-desktop) so it didn't work.
I used to need to remote into a client's machine with AZERTY. It was impossible to type the password. Every key-stroke showed a *, so there were no hints that an alternative keyboard was used.
Wait, the remote tunneling software you used wasn't smart enough to automatically convert keyboard strokes? I didn't even know that was necessary, but wow.
I have not used an alternative Keyboard layout recently, but when I did (when I was still using Windows, and not Linux Mint) I used Microsoft Keyboard Layout Creator.
On Linux Mint, I tried to get Microsoft Keyboard Layout Creator Work with Wine, which did not work.
EDIT: I think I had a post on how to make a keyboard layout. If you can find it, it may prove helpful to you, hopefully.