Another one I've looked at is Flexiserv www flexiserv com. They seem to do good 1u, half-depth, cases.
I am, however, not able to make the additional investment required in a 1u case work out cheaper over a couple of years than a 2u case for the same application. (2u cases are quite cheap from somewhere like Dabs.com). Given the price of rack space these days, it's actually as cheap if not cheaper for me to use a 2u case with a lower memory capacity.