You can't open the top of the Signum Data units to get the 5-6 card effect: they use micro ATX mobos ... they won't have enough PCI slots even if you could stand them up. I think you would need three of those suckers to accomodate that many cards. If you aren't looking for extreme cooling, then there are ways to fit everything into ONE 2U or 3U case by using BI Micro style rads and micro-inline pumps combined with a block that has side barbs. In
http://forums.procooling.com/vbb/sho...&threadid=3321 they show a micro-inline pump. Combine those, and you'll fit in a 3U easily, though you'll be looking at air temps ... but if that's no biggie, why worry? If you are looking for total silence, put it all except the rad in a 3U and use a massive radiator mounted to the top outside of the case for passive cooling. You'd have a completely passive unit. You'd want to run a P4, methinks, for the lower heat outputs.