Very interesting indeed!
You are probably aware that there is some activity on Digital ATV and the boards made
for that purpose (and/or the cheap dongles they use) could be used for this as well.
We have a Digital ATV repeater here that is currently under some reconstruction, and I
have suggested putting some IP broadcast on the multiplex. Indeed, as you note, a
Linux-based DVB receiver can easily put the demodulated and extracted IP traffic on its
LAN interface. More than a decade ago I did some "experiment" logging the
downlink of
satellite-internet on a Dreambox and it just used standard features of its software.
But your test of using this full-duplex (rather than just unidirectional as it was
envisioned)
surely is innovative.
It could be useful here as well, indeed as you indicate to make links on amateur bands
for which there is no commercial WiFi equipment. It is not straightforward to use that
equipment with transverters, and a steady fullduplex link would certainly be easier.
Some people are also working on a 70cm digital access with smaller bandwidth, there is
little detail on what modulation they use, it would be interesting to see if using DVB-T2
in halfduplex more is feasible. Probably not, due to high turnaround delays.
Rob