Have you looked at "Add custom timing mode" or similar? That should let you do all kinds of fun and interesting resolution tricks. It's not one of the things easily exposed in Windows and I no longer have the guide, so you'll have to find it yourself; in Linux you'd add additional metamodes in xorg.conf. (You _REALLY_ need to be careful with custom timing and a CRT, though)
Also, in Linux you have pretty fine-grained control over scaling - there is no global scaling tickbox; you instead
define special metamodes with the exact input resolution and output boundaries you want. You can even forgo specifying resolutions and apply an actual transformation matrix to mimic CRT curvature. Not sure offhand how to make it not blur on an LCD if you're using an exact multiple, but realistically for me it either doesn't bother me much or I'm running it through filters like Blargg's NTSC anyways vOv