I have seen in giri traders in chennai for downloading various songs in MP3 format - to usb stick or ipod for a fee. Here is another product for downloading music content through a network. I am not sure about technical details, but seem to be a good concept. If we can have a huge collection (like in sangeethapriya) and other archives that MAA/Shanmukhananda, and other personal collections in a common server, and with help of these boxes, we can download the concerts pretty fast...
http://www.dmobili.com/products
-hari