It's more and more difficult to find anything that doesn't OFFER surround sound, but just because it's more than you need doesn't mean that it doesn't also deliver exactly what you need for two channel audio...
http://www.d-mpro.com/users/folder.asp?FolderID=4214&CatID=17&SubCatID=165
The DN-A7100 is a nifty model which is a surround pre-amp but includes balanced audio input/outputs with a rack design from the start. Stereo is obviously just part of what it does.
If this doesn't work, then your best luck would be to go with some other 'pro' product, or to find something you like and get a Middle Atlantic rack shelf for it.