I read your writeup on the A900 and found it beyond useful. I'm known as a bit....impulsive..... over at dyxum, but I really thought this out and came to some conclusions:
1) I know the increased aperture demands from a narrower DOF will make a lot of my A700 shots poorly focused/impossible.
2) I found I really love landscapes and nature "scenes", so I figured a more medium-formatish camera would be perfect.
3) As great as my lens lineup was (especially the CZ 16-80mm), it always felt overpriced and a bit "cheap". It's hard to pay almost $600 for a lens that has the build quality of a can of Pringles.
4) I love 1:1 view!
5) I'd like to start actually making some money off of my obsession, and I figure that delivering a 20MB jpeg to a prospective buyer can do nothing but help
6) I've still got an A300 sitting about, so if I feel the need for speed I'll grab that.
7) The viewfinder! (it's...it's... full of stars!)
9) Being able to achieve TRULY selective focus, and not getting a migraine doing so
10) RAW headroom! I have so many blwon highlights from morning/dusk landscape shots that I stopped keeping track. I despise HDR (and it's a pain to process without it looking like a lame cartoon), but it's often the only way to extract what I want from my shots. An example:

11) Silently scoffing at the CanNikon folks and their lesser cameras..... j/k....kinda.
PS it feels funny to buy the most cutting edge camera around, then proceed to sell all my fancy digital lenses and equip it with film dinosaurs. The dichotomy of it all.......