Gees that was me that did the skin?
Yeah, it is totally geared as a music server, and I stripped alot of the extras out, but with some time, and patience, stuff can be added.
I don't have an RF remote, I'm purely controlling the system via PPC, but if you have something that is already connected to the computer (ATI type of remote I just found out the other day), then you should be able to setup some additional/modify current events to remote control the skin. You will just have to look on the forums to find out how others have setup control using a RF remote, then get aquainted with skinning. Takes time, but the learning process is soooo much fun. As I've said before (maybe not exactly this way but...), consider my skin as a template. Once you have an understanding of how it works, then have all the joy in the world changing it to work better in your setup.
Internet control could be added, just by adding the extra screens. Following some skins geared to more general HTPC uses, you could strip from them the things you need and add them to this skin, no problems. I've done a skin called Mirage that I have different types of "internet" access...from browser, to RSS feed, to YouTube video, and webcam images. Download skin's by Buddabing (can be found on sharp's googlepages...look for posts by sharp_1, then click on his link in his signature), or Colby's skins. I've found them to be riddled with information to learn and use in for my own creations.
Adding TV, in that, do you mean distributing just the audio around to different zones, or are you meaning video as well? First, is the TV input from a set-top box? or is it a tuner card? If via set-top, then you could do something like what I have done with my AM/FM tuner, and that is by inputting the signals into the sound card's line-in, then setting up that particular input in the KX drivers. To let you know, the next phase of my project will be building a 4x2 Audio Matrix switch, which will alow for an additional 3 sources along with the tuner to be plugged into the two soundcards line in and then users on the mainfloor will then be allowed to select different external devices to listen to from users upstairs. This way along with the tuner, I can have an IPOD dock, TV, and DVD player and users can select to listen to music or soundtracks per floor...as opposed to the current setup where the only external device is a tuner, and all users on both floors only have the option of listening to the same station. If I pull this off, man-o-man, this will give 3 sources of MP3/shoutcast playback, and upto 4 sources of external device playback PER floor (and then add the whole house audio source too).
Anyways back on topic, if your thinking of running video too, then there will be some work involved. I'm not sure how many video outputs you can run from one system. One of the easier options is then to set up additional xlobby's as fat clients on your network. Store all the video on the main HTPC in shared directories, then each fat client that connects will copy the databases over, allowing playback of media that way. One day, if I ever get a main HTPC setup for myself, I'm going to be doing something along that lines but with my music. It will connect to the music server and be able to access all the music direct from the server as opposed to storing all the music on the HTPC as well.
Oh boy, lot's of options.