Another option I thought of was using a digital switch.. such as this ... http://www.ebay.com/itm/400312722729?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_1950wt_1095
I could use it to interrupt the data transmission in the cable (seems there are 3 separate data channels in HDMI).
Anyone have experience with this type of digital switch ? I was looking for an 8 bit one but there don't seem to be any around in the DIP package style.