Just recently got my hands on a dockstar (basically a sheevaplug or something similar with less RAM) and I've been having a lot of fun with that after getting arch linux on it. The RT-N16's USB read speeds were on the slow side so it was nice having a dedicated NAS with Samba.
The truth is, I'm new to Linux, and it took me a lot of googling to get Samba working the way I wanted it to. When I started doing research for my next project, getting captive portal working on a router running tomato, I realized there wasn't much work already done with tomato and captive portals. And I really don't want to switch to DD-WRT.
One of the most interesting resources I found was http://www.tocpcs.com/setting-up-chillispot-with-freeradius-on-tomato/
and I'm just wondering if that guide by itself is enough to get a captive portal up and running, as long as I'm willing to put in the time and energy into it.