Raspberry Pi as remote control via internet.

I've had thoughts for some time about whether a Raspberry Pi could be used as a remote control to turn on my HDR. The idea is that it would run a webserver with PHP that would allow you to get the Pi to activate an infrared LED via the GPIO port and send the On/Off signal to turn on the HDR. If you also have some kind of proxy running on it you could make it take the webif on the HDR and proxy it into a frame on the Pi. You then forward an unusual port on the router to the Pi which would allow you to talk to the webif via the Pi if the HDR was on or send an ON signal to the HDR, wait a bit and then talk to the webif. This would mean you don't have to have 2 ports open on the router, 1 for the Pi and 1 for the HDR. If you have a wireless connection to the HDR, the Pi could scan for the webif on a range of IP addresses in case it had been assigned a new IP address since the router was setup.
This would mean you don't need to either have the HDR on all the time while away or have it keep coming on so you can program it with new recordings, either via the RS package or direct via your router.

What do people think?
I have had a similar idea, but dismissed it for further investigation because my goal includes being able to salvage power from the Ethernet (or somewhere else) and the RPi is far too hungry for that. Something with much less grunt will be enough for this task, probably a PIC.
Could you program a PIC to be a webserver? I've used them for simple serial communications but never tried to squeeze anything like a webserver into one.
There's an EPE project which did it, but I was thinking of something much simpler to monitor the Ethernet traffic and send an IR pulse in response to a ping on a specific IP address. That's all you need really.
It crosses my mind that having an RPi powered up all the time just to turn the HDR on, you might as well just leave the HDR on all the time.
It would be doing other things too like controlling the central heating. Leaving the HDR on all the time would knacker the hard disk because it would be recording the live channel all the time.
Oh well, if it's going to do other jobs too it won't be a universal app. The live buffer doesn't record data channels - I leave my "media server" on 105.