Is your motherboard full ATX or M-ATX.
With M-ATX you can find smaller cases.
About what are the dimensions that will suit your space?
I had a space problem with cases that are longer than 16"
How much do you value quiet?
My take is that if a case has two 140mm front intake fans, you can get what you want.
140mm fans move enough air at low rpm to do the job and be quier.
If those two fans are filtered, you will have a positive pressure situation where little dust buildup will occur.
My case sits behind a single 200mm filtered fan and there is no dust buildup.
Looking at the options presented, The Corsair 450D looks good to me.