Running off of the router

Hello, I very much like the idea of subsonic. However I was wondering, since I do not have a 24/7 always-on pc (even if not for electricity costs, for that awful fan noise) whereas this is exactly the case for the router (like most home users I'd guess) can I not just attach an external HDD to my router and run subsonic thru there? Not sure if this would be possible, but since there are open-source firmwares(like dd-wrt) for routers these days, maybe adding subsonic support would be trivial?
Scouring the faq & forums I didn't come across something like this, so would anyone think this is a feasible idea?
Scouring the faq & forums I didn't come across something like this, so would anyone think this is a feasible idea?