Today we saw a lot of news about the new camera from Canon, the 450D.
It comes with Live View which is really nice for focusing especially with a telescope, however, the increase in the pixel count will probably also increase the amount of noise for deep sky imaging.
Also, just like 400D, the dust removing system will likely make the removal of the low pass filter harder than before. With the low pass filter in place, the sensitivity for H-alpha signal is going to be weak, that means it's not very good for deep sky imaging.
To me, I'm considering a DSLR again mostly due to the upcoming total solar eclipse, for that matter, the low pass filter and the increased noise level shouldn't be very important. However, Live View will definitely help in focusing, especially if there's no big sunspot on the solar disc. So, I actually consider this camera more suitable than 350D/400D.
And I guess Canon will probably discontinue 400D when 450D finally comes out, but I believe 350D will be here to stay for one year or two, to target on the really entry level market. It would always be nice to buy a 350D later for modification, if one day I'm interested and have more time for deep sky imaging.
Remarks: the estimation on the noise level is pure speculation, we can only tell when it comes out; again, the H-alpha sensitivity is also yet to be checked.