As odd as this may be, i get great use out of my 1100d. Mind you i have only had a chance to use it in autumn/winter so i cant comment on summer experiences, but noise was fairly tame.
Modded it myself with instructions from Gary, so it set me back about $400 brand new.
See some details on it and other DSLR's here
http://ghonis2.ho8.com/T3review/T3review.html
It's very similar to the 450d in specs and noise is comparable.
Might be worth considering if you fancy your hand at modding it yourself (no additional parts needed).