2FastCPU have just posted a review of a new heatsink... namely the Arkua Technology 6258. It looks very similar to the ThermoSonic ones, but let's see if it works like them as well. here's a snip:
"This heatsink incorporates ThermoSonic's 'X'-Radiating Design. Arkua has been authorized by ThermoSonic to market and sell all Thermosonic products exclusively. ThermoSonic themselves, has a similar version of this heatsink, the XC60-2525."