recommendations for LCD monitor arms + sit-stand setups

So I was reading articles about how sitting all the time will kill you. Being a programmer, I sit all day at my job and then I get home and sit at my home computer. I figured I'd break this up by setting up my home office as a convertible sit-stand workstation. Hopefully there are other forum members out there who have done the same and who can advise me on how best to set this up.

Currently, the equipment I have to start out with is:

* an IKEA GALANT corner desk
* a Mac Pro
* a 20" Dell LCD and a 22" Samsung LCD

I can't replace the desk, so I can't get one of those IKEA Jerker adjustable desks. Given that, I was thinking I'd get a couple of LCD monitor arms to attach to the desk and a lap tray. That way, to stand at my desk I could raise the monitors and then put the keyboard + trackball on the lap tray, which itself would sit on top of the desk.

For the LCD monitor arm, I'm looking at the Ergotron LX desk mount LCD arm, but it doesn't look like it'd be able to lift high enough for when I'm standing. Any recommendations?

Anyone else converted a non-sit-stand desk into a sit-stand workstation? How did you do it, and with what equipment?

I saw an astonishing improvisation at a war veterans' home recently. A tall, like 1.3 m, walking frame, with arm rests and hand grips. The old guy, in his 80's, had mounted, on the front of the walking frame, a tray, on which rested his laptop! [His body was worn out, but not his brain.]

You could modify such a frame to accommodate your keyboard and mouse for wireless operation of your Mac Pro. What's more, you'd get some exercise for your legs as you moved about, thus avoiding the dreaded DVT!

You'd need to raise the working height of the monitor, but that would be a simple enough matter.