I had this same question.
I have my Panasonic Plasma mounted to an OmniMount TV stand (moda 50fp) and the columns that support the TV conveniently block ALL my component connections and one of my hdmi. The hdmi was easy to sort out as right angle adapters are readily available. The component connections were a different matter... I had really two choices:
a) buy some RCA right angle connectors and pray that the loss wasn't enough to affect my video signal (1080i cable TV and 1080i HD-DVD).
b) buy some very expensive, very cheap looking, Monster Cable "FlatScreen" cables which terminate in stubby little connectors that can be just barely squeezed in between the back panel and the column- and then pray that the resulting sharp bend in the cable didn't degrade the signal or ruin the cable itself.
Currently I'm using the Monster solution and the results seem to be satisfactory with the exception that I'm worried that the resultant pressure of such a sharp bend is either ruining the cable or applying un-due stress on the connectors. Any advice for me out there?
What to do if you find yourself stuck with no hope of rescue:
Consider yourself lucky that life has been good to you so far. Alternatively, if life hasn't been good to you so far, which given your present circumstances seems to be more likely, consider yourself lucky that it won't be troubling you much longer...
-- Excerpt from the Hitchhiker's Guide to the Galaxy.