Yes, the cards are easy to get hold of and install - 4 screws and it's like putting in a PCI card.
Depending on the panel version that you have you should find the right blade to do the job. I think you are on the west cost of the USA, so try:
http://shopbig.com/ty-fb8hm-panasonic/search-html - this is for the 8 and 9-series panel. There is adifferent one for 6 and 7 series panels. (fb7hm)
I'm not convinced of connecting the IR puck to the Beovision 4 directly as the codes to control the TV are completely different via the serial port. I did upload *years* ago the serial protocol and commands to this site, but don't know where it went.
The Lintronic box would, of course do the job
If you want to use Beo5, you'll still have to drill a hole through the aluminium bezel for the remote sensor of the screen to work!