The LX9 used is the largest Spartan 6 in TQFP format/package, after that it's 324 BGA upto the LX45. Apparently the PapilioPro went with the LX9 because the guy who makes them has had trouble with bringing BGA to market before. The Pipistrello is made independently by someone else entirely.
As for the HDMI/DVI thing there's a thread where someone has made HDMI adapter already and supplied the schematic.
Like I say, might be a nice hobby board for learning/prototyping on for those who are interested in it.