Only way I can think of interfacing your existing door contacts to X10 is with a Power Flash (PSC01). With that, you wouldn't need a transceiver since it would send an X10 signal direct to the power lines to activate a light switch. But of course that depends if you existing system can be wired to the Power Flash.
I have seen blind / drape controllers at automatedoutlet.com, I don't have anything like that now so I can't really give details on the how to's, but I'm sure a Universal Module (PUM01) would come into play.