Welcome to the forum,
1) Yes you will need to chip the box, the Schematics are in Micks how to guide.
2) It will probly be easyer to mod the files on your box yourself rather than download them form the wiki as i think they are for the german boxes. you just need to patch the NK.bin, and replace the booterce.exe and booterce.dll files with the ones in the wiki( they should be there if not i can upload them for you.)
3) Curently we have it watching TV and getting EIT now and next data for the TV guide and it displays the recording menu but wont record because of the intergration with the webservice.
4) from what we have seen in the code it is capable of media streaming from lan aswell as the standard PVR functions you get from a bt vision box as for usb functions i dont really know i would assume there would be a way to pull music and videos from a memory stick or similar but thats quite a while away.
It would be good to get another programmer on board as we have 2 very good c# programmers working on it and myself and i can work out the logic but im by no means a c# expert.
you would also need to replace the TV2ClientCE.exe that is in the NK.bin with a modded version but unfortunatly because its a copyrighted file i cannot post it on here and offer it for download.