I had seen that before, and kind of dismissed it. I did a quick scan of the user's guide from the Linksys website and couldn't determine whether it spoke SMB or required some client side software. So, I just assumed it wouldn't work and moved on.

So, since you mentioned it, I looked around again to find that, yes, it does speak SMB, and it actually does run Linux (and replacement firmwares exist). I haven't found any reference to anyone running a Rio Receiver server or Slim server on it, but I would assume it's possible. Even if not, some of the playback boxes I'm looking at (like the Roku HD1000 or the Audiotron) just scan an SMB share, so that works.

Here's the problem I have with the NSLU2, now: It's not a single box. To put 500GB of storage on it would mean I would have the NSLU2, its power supply, two hard drive boxes, two USB cables to connect them, and possibly power supplies for the two hard drives (since I have no idea if the hard drives I would use exceed the power available on the USB ports). That mess would not be nearly as elegant as a single box would. I wouldn't be able to as easily move it from one spot to another, or pick the whole assembly up and take it to work (where my library currently resides) for the initial loading of music. Sure, I could always duct tape all the pieces together, but I think I'll keep looking a little bit further.

Having said all that, the NSLU2 really comes close to what I'm looking for. So, anyone know of something like that in a single box?

Other solutions I've looked at: Mini-ITX boxes like the Shuttles seem attractive, but they seem to be designed with the idea to cram the most powerful system possible into the smallest space. Plus, they're usually super loaded with all sorts of things I don't need or want for this application. The ones from SolarPC look good, but the cases aren't big enough to hold two normal size hard drives unless I spend too much, and even then I get a 2U case much bigger than what I need. There are lots of SBC boards that might work, but I don't know anything about what cases might be available for them and whether any of those would work. In addition, an SBC is probably too expensive since it's geared towards vertical markets.

So, any other ideas? Here's a nearly meaningless incentive: I'll PayPal $5 USD to whomever suggests the solution closest to whatever I finally end up with.