@ThomasM, that's an interesting project and you've documented your progress well.
I'm particularly interested in the RF receiver part of the project. That Infineon part just looks like a regular ASK receiver / decoder, so I assume it would be directly equivalent to something like an RXB1 or RXB6 receiver module like the one used in the "Weather Station Receiver" project in Practical Arduino. If so, the hardware designed for that project should be a direct drop-in replacement and with your code could possibly be used with X-10 wireless transmitters. I designed a simple shield that incorporates that module:
Being able to use it with X-10 transmitters would be cool. I have a feeling my X-10 transmitters may be 315MHz though, not 433MHz. I'll have to check when I get home.
Jon
Practical Arduino: www.practicalarduino.com