Kinesis is also super hacker friendly. If you email them and ask they'll sell keyboards without the keyswitches so you can put in cherry blue or cherry clear switches. They've also been very willing to provide technical information - they sent me mechanical diagrams of the main PCB so I could build a replacement controller running custom firmware, as well as part numbers for the ZIF connectors.
I've been using a Kinesis (Ergo Elan) for 9 years now. After about 5 years some of the little rubber keys started malfunctioning. Now my ESC and F5 keys no longer work at all and most other rubber keys only intermittently. I probably should open it up and apply graphite rubber to the keys to restore their ability to make contact.
I don't mind the size of the rubber keys, but I wish they'd make a keyboard with decent switches for them!
What would you use as a pointing device with the Kinesis though?
I've grown quite attached to the RollerMouse classic over the years as the ultimate pointing device but I'm wondering how that would work with the Kinesis.
Hacking a trackpad in the middle also seems like an odd compromise ...
It's what the other Kinesis users around me were using and it's the only wired touchpad that could fit. It's a piece of garbage and I've given up on it. I've fallen back on using my Evoluent Vertical Mouse, as it's the only mouse that doesn't leave me in pain.
The real answer is that I've adapted my tools and workflow to be as keyboard operational as possible, using a tiling window manager, Emacs, and Conkeror for everything.
I got a review copy of the Kinesis Advantage, tried the keyboard for a while, wrote a review (http://jseliger.wordpress.com/2009/07/20/kinesis-advantage/), sent back the review copy, and, a couple weeks later, bought the Advantage.
YMMV, but I think they have a somewhat long return period in part to assuage people in your situation.