Suggest a quiet mobo for mounting in an inverted case

[Munky]

I'm planning to build a quiet rig, and the case I have decided on will hold the mobo upside-down. I've heard that this will cause a problem for the heatpipe-based mobo cooling solutions, so I'd like some suggestions for the best alternative. I need a s939 board with a PCIe slot, ATX form factor, and something that has a silent or quiet chipset cooler but can also be safely mounted upside-down.