I'm watching this one, but having looked at the Kel-Tec site I am more then a little worried about the complexity of this system, and how it will hold up to heavy use or dirt. I would have rather they designed a more "traditional" bullpup that would have allowed conversion for left to right hand ejection. While I haven't kept up on the latest concerning the FN Bullpup, I do recall reading that it is prone to a particularly nasty jams do to it's unique ejection. That would concern me with this design as well. In my opinion the lack of ejection port access might make "simple" jams into "horrible-gotta-field-strip" jams.
I would really like this design to work out and be wonderful, but I have strong doubts about any weapon that attempts a "new" ejection technique.
P.S. I do like the use of FAL mags though. Honestly wish the XCR-M was coming with FAL mags.