Most small cases that hold a regular ATX PSU are wide, except for slim cases which use nonstandard PSUs. Are there any which mount a regular ATX PSU vertically so that you can have a narrower (but taller) case? This would require an intake to be on the side rather than the bottom, but it would make for a much thinner case.

Something like this?

http://www.amazon.com/Sentey-Ss2-2232-S ... d_sxp_f_pt

It hasn't got the PSU at the rear of the case, but it does mount it sideways/vertically, allowing the case to be narrower than standard.

Another one I can think of is the Coolermaster Elite 360.

http://www.youtube.com/watch?v=tiFk5BO23SA

Lian Li have been making cases for years that are arranged like this.

I also have the Silverstone SG03 which is arranged like this. It does limit CPU cooler height but can still be run semi-passively when fed by cool air from the front.

That's the config I was thinking of at first too, but I'm pretty sure the OP is thinking of a standard ATX tower design, but with the PSU rotated 90 degrees in its same location. Thus making the case a little taller and narrower, rather than shorter and wider.



Source

Ah, now I see that now. Basically like a lot of desktop cases really. This does mean that a full size optical drive can not be used horizontally as this is the same width as a PSU.

Thanks for the tips everyone. I realized that what I was looking for wouldn't really exist. By making it slim, only half height cards could be used, and one of the main reasons to have a regular PSU would be for something like a video card.

The Lian-Li Q07 is pretty close though; one of my issues with the "breadboxes" was how deep they were.

Full-height cards require about 12cm, PSUs about 15cm. Cases like BitFenix Outlaw are 18cm wide.
What width are you looking for?
If you want really thin, get the Q12 at just 88mm.