I am also building a PVR solution and am hoping LinuxBIOS will help the startup time (and be a neat project).
And this EPIA pops up everywhere on PVR pages, but it has only 2 PCI slots... very dificult to decide...
You should also be aware that the EPIA processors are not the fastest. If you use the PVR-350 and use its hardware MPEG2 compression and decompression you should be ok. But, if you try to use the epia's cpu to compress and/or decompress you could hit the cpu limits.
I'm currently using EPIA-M's with MythTV (http://mythtv.org) and am quite happy with them. My project is described at http://linpvr.org.
I would be happy to talk to you about my experience. It's off-topic for this list but you can email me or use the forum on my website.
I currently have LinuxBIOS loading etherboot as the payload and that loads a kernel over the net. I don't have VGA working yet but I understand that has been done by others so I'm hopeful this will work out.
Larry