Just got into the whole split KB thing after noticing I'm starting to see some RSI-like symptoms working some long days/nights/weekends.
I had been using a full-sized Unicomp (IBM buckling spring) for years, which was/is awesome, along with a Logitech M570 Trackman wheel previously.
Picked up a Matias Ergo Pro, which is a wonderful design but not reliable enough for me to continue using, let alone buy a second one (doubling after a month of use), so currently using a pair of Mistel Barocco KBs while waiting to see if/when the UHK comes out, or better yet, something like the Ergo Pro in a > 60% layout (just split ESC and arrow keys out and I'm golden).
One of the very nice things on the Ergo Pro was the wrist-rest; in combination with my desk, chair, ... it was 'just right.' As the Ergo Pro will be disappearing from my desk shortly (once my second MB w/Blues shows up), I'm going to miss both the tenting and the lack of wrist-rest. This isn't a big deal at home, where I use a keyboard tray and proper chair and arm positioning, but at work I'm a bit more limited so even with the ($$ ergo human) chair fully raised and arms positioned correctly, the wrist rests were nice in use.
Does anyone make a rest suitable for split keyboards currently, and if so - who, where, experiences w/same?