I am in a similar position to the Op, I have an A700 with some ok lenses and one very good one (70-200 2.8G) and was looking forward to the A900, which, if I could justify to myself, I could afford.
I am a bit disappointed too that they sacrificed noise for megapixels and so have decided to hang back, particularly as I would need to sell my Sigma 28-70 2.8 and Sigma 10-20mm and replace them with the Zeiss equivalents (£1500 upgrade cost).
I have two options.
1. Sell all my kit and go for either the Nikon D700 or D3 or Canon 5DmkII with a line up of lenses.
2. Hang back and wait for Sony to bring out their next full frame sensor camera, which may be lower resolution, better noise and include HD video, something I would quite like.
At the moment I'm leaning towards the second option because, if truth be told, I enjoy using my A700 and don't find it that limiting, it's just that it would be nice to shoot at ISO 1600 and have usable colour images.