I haven't seen this request yet, but I'd sure like to see PB available for Solaris. Now that Solaris is available for free for x86 hardware, this will become more and more important.
Less important, but nice would be a version for HP Nonstop server hardware.
I'm sure Solaris and Nonstop users would be willing to shell out a good amount of cash for such a product.
The question isn't how many people have Solaris and want PB on it, but how many people have Solaris would be excited to purchase PB once they tried it out on their platform.
Maybe even Sun would want to support such a project to improve the demand for their servers and/or OS.
How about PB on AIX. I reckon Fred already has done most of the work. The Power MAC uses an IBM RISC CPU. OSX is BSD based, There's a Linux version as well. All the hard stuff is done and of course AIX on Power RISC CPUs is a safe bet (IBM isn't going to drop its flagship CPU Architecture like HP or Apple did)
