Hi Beowulfe
Your core seems to be more than adeguate, as long as all of your capturing hardware is well supported in Kubuntu.
I think you may get into some troubles with wireless.
All MDs boot off network, and so far I never heard any success story about a MD PXE booting over a wireless connection.
If your concern is about re-running cables all over the house, a good alternative could be using power lines.
There are many nice and not so expensive adaptors that you plug into ac mains and on the other side offers a RJ45 socket. I remember well there are some devices that can offer 200 MBps.
I've seen those devices on internet some times ago and I think I mentioned them in another post of this forum.
I think that googling around you may find a lot of useful pointers.
HTH
Marco