Disclaimer: I don't own any LaCie equipment.
BUT:
Few things I think I can contribute based on my experience with HTPC and general knowledge of LaCie in general.
I think (krzywica can correct me if I'm wrong) LaCinema looks like another glorified NMT/PCH unit with list of very similar functionalities.
One thing strikes irregular from their
specs sheet:
Digital Audio : Multichannel decoding via Optical audio and HDMI to digital home amplifier
DTS® : DTS, DTS-HD: Pass-Through via optical audio
Dolby® : Dolby 2.0: Decode, Dolby 5.1: Downmixing and Decode, Dolby True HD: Passthrough via optical audio
As far as I know - you just CAN'T pass-through neither TrueHD or Dts HD over spd/if (ether coax or optical), only over HDMI 1.3 connection.
IMO you really want to have network connectivity in your media client. In addition to Wifi you can try getting pair PowerLine adapters.
p.s.s: LaCinema wont play DVD menus....