clustering is not really practical for games normal programs emulators etc... it is for scientific high bandwidth calculations etc... this is due to the latency between the CPUs among other things of course if you wanted to use it as a render (ie povray...) farm etc that would be doable but rather pointless as well....
also you would have to use a cross platform clustering system like grid or the java clustering environment because the pandora can't run x86 code
also clusters need VERY fast networks to work properly at least 100mb ethernet while gig ethernet would be better
I have some experience with a cluster and they are pretty difficult to setup... esp if software you are trying to run is fighting you tooth and nail.... WRF a weather research program