If you're looking to house 2xCards the Dell T3500 an extremely cheap option and it is solid. They sell for peanuts, I got a X5675 (hex core @ 3.06GHz), 12GB RAM, 500GB drive and NVidia Passive graphics card for £150 inc del. Its quiet and takes my 2xUAD1 cards. Also came with Win7 Pro. Most stable Scope machine I've ever had but wish it would take 3 cards

Anyway, cheap is deep lol.
Regards,
CGF