rPi & ASICMiner Block Limit?
I have used both Debian and Arch Linux on an rPi to run Butterfly Labs mining equipment; the rPi was able to handle up to 9 SC Singles with CPU to spare using recent versions of both bfgminer and cgminer. So I suspect that it would not have any difficulty driving eight Block Erupters.

Be sure to take some care in choosing your USB hub (it will need to be powered) and you may find MinePeon to be a useful package for getting things set up.