Simply a great idea. Torrents always outperform mirrors, which by definition could also seed the torrents. Faster downloads, plus a greater sense of community. Thanks.
You are rightfully cautious with the origin of executable code. However, Torrents have built-in precautions against tampering in the form of hash codes. Every time you download a chunk of information as a part of a torrent, it is checked for its hash code.
Also, this way I wouldn't have to download the update separately for each of my machines. Upgrade my home server first and then the others would get the updates directly over the high-speed LAN connection.
With hash checking it would be very hard to sneak executable code into people's packages. Possible, but unlikely.