I never had issues with LP-coolers on the intel-spec mITX-boards. All the Gigabyte-boards have the socket close to the PCIe x16 and I can fit most LP-coolers there without blocking the PCIe x16. If big things like the Thermalright AXP-200 does fit (and btw... the Pallas is basically a clone of the AXP-200), then I guess everything else will too. The Samuel 17 from Prolimatech is also a good fit on mITX-boards with the socket close to the PCIe x16. EDIT: Clearance for the TR AXP-200 which is basically exactly the same, strapped to a mITX-board with standard socket-positioning. It's actually pretty much what you're after for a mITX-system, as it cools all components on the board, has enough clearance for standard DDR3-DIMMs and doesn't block the PCIe x16 slot. Even a picoPSU would fit perfectly under this heatsink and get cooled.