Edit - I think the Zippy 400W is probably the best option from Servercase. The H1H-6507P (40A 12v rail) would be the best match though only 20mm under the length requirement, but Servercase doesn't sell it
Thanks Oklahoma Wolf, it's much appreciated. Funny thing is that the website lists its address, and it's only a couple miles from where I am. I may just drop by and see what they have. Thanks once again.