I was for awhile running 1080i from my Tivo, and 1080p from Xbox360 and PC, to my bedroom from the living room (in my last apt). From the 4x2 monoprice HDMI matrix switch in the living room, the output to the bedroom went through as 12' cable, faceplate w/ cable saver, 15' cable, another faceplate, then 30' cable and then plugged into a 2 port HDMI switch (which I used solely because it output any DD/DTS/2.0 PCM over toslink to my old receiver in the bedroom). All cables / wall plates and matrix switch from monoprice, the small switch in the bedroom was from ebay.
I did have problems before putting in a switch at the end of that chain going direct to the Moome card in my old NEC ISS, but using an old 5 port 1.1 switch from monoprice (prior to the one w/ the SPDIF out) fixed that.
So, you can actually go pretty far and with some crazy combinations but it will depend on your gear. If it doesn't work, throw in some switches that have equalizers and it may save the day.
(I'm not running this insane setup at this point and have nothing in the bedroom yet, I recently moved to a house and haven't yet wired everything up but will be going the structured wiring route)