I must say I got a good feeling from Alan's A1 roadmap.
I am thinking of building my own SE board into a 1U rack unit, but I think it would be a tight squeeze with the new memory module I bought from Gunne this weekend.
However, I can see these as good selling points for the AmigaOne:
The firmware (U-Boot) will use serial port for stdin/stdout if you set the environment variables stdin/stdout to serial OR you remove the keyboard/vga card (autodetects...). Thus, you don't need a VGA card or a keyboard for a render-farm.
It has 66MHz PCI if you have a RAID controller or a gigabit ethernet card. Running in a 1U rack box without VGA but with IDE/SCSI RAID or GBE would make for quite a nice server, actually.
It uses hardly ANY power. 3W for the 750FX CPU? Dang, man. Might as well be zero when you compare to other platforms.
Look out for a 1U amigaone coming to a rack near you :-)
Addendum:
Check out a 32x32 RS232 crosspoint matrix here:
Network Electronics website, D3232 product page