All of the Hauppauge cards only have one frontend. The "big" cards
(just called DVB-[SCT] or Nexus cards) have one hardware demultiplexer.
The Nova cards have no demultiplexer. They only deliver the complete
transport stream which is then demultiplexed in software.
So which cards do you talk about in your paper from Linux Kongress (p9) when you say that newer hardware even offers several frontends, demuxers and decoders on a single chip?
Do they exist for DVB-T?
Such solutions are more usual in the SetTopBox market, see e.g.
Zarlink's 1031x family, this provides 2 OFDM demodulators, demux
channels and MPEG-decoders on a single chip. Other vendors ship chips
with multiple demuxes and decoders, too.