Yes, I like the idea but I wonder if there is a market for this. One could even connect this to their set top box or VCR/DVR, or use it directly as output on the television. While doing so, you still have the tablet in your hand and are able to multitask. I've been tinkering about building my own DVR, using the tablet as remote control. This can be done cheap, say with e.g. CherryPC, although then you lack hardware MPEG2/MPEG4. Or VIA, who have released some new open source drivers for their hardware.

For remote display I suggest NoMachine NX (or FreeNX + one of the open source clients) because this easily allows remote X with resuming of session, good compression, encryption, and easy way to define available connection bandwidth (from 56k6 to LAN similar to RDP). Clients are available for Windows, Linux, MacOS X, and some embedded devices. Another option is X + VNC + XRDP with Rdesktop client. The latter is even more widely available. This is a bit ugly due to protocol overhead on the server. VNC means slow bandwidth, but very cross platform.