I have a Gemini also, and have backed the Astro Slide. However, I think the Gemini fits in that very awkward space where the keyboard is too small to touch type on, yet too big to use in handheld mode. I much prefer the slide out keyboard on the Nokia N810 (but still wouldn't be able to "code" on it).

The best micro keyboard I've ever typed on is an Apple Newton keyboard that I interfaced with a Palm Pilot. The key spacing is 90% of a regular keyboard, which is about the smallest I can go and still touch type. I really wish I had a modern day portable device with this keyboard form factor.