At my desk, I use a Dvorak keyboard. However, I often need to rip my laptop away from my desk for meetings, emergencies, etc. When I'm typing on the laptop, I use Qwerty. It's not a problem at all. I don't need to think about it; my hands just do the right thing depending upon where I'm typing.
I've been pretty consistent about only using dvorak on split keyboards, and only typing QWERTY on non-split keyboards. This has done a pretty good job of keeping my muscle memory for both separate. My QWERTY typing is a bit rusty, but I can still manage up to 60wpm when using my laptop, and I don't have to pay too much attention to what my fingers are doing. Though when I use QWERTY on a split keyboard I have to watch my fingers.
(These environmental cues can be funny sometimes - if I use emacs for editing C++, which I do only very rarely, I keep missing out semicolons. Because most of the time, if I'm programming, and my eyes can see emacs, my fingers know I'm using python.)
It's good to hear that. Being afraid of forgetting how to touch type on a qwerty was one of the reasons I never made the plunge into alternative keyboard layouts.
Though, now that I think about it, alternating between keyboard layouts is really no different than using a modal editor like vim -- after a while it just becomes second-nature.
