Bruce, it may be way more complexity than you're looking for, but have you considered running an Asterisk box? You can get one of the all-in-one distributions like PIAF (PBX-In-A-Flash, what I use), run on any hardware, get a VOIP termination / origination vendor (I use voip.ms, have a couple of backup vendors) and you get all the telephony capability you'd ever want. You can run it on practically any hardware, so the only cost would be your time and you'll probably want to get one of the linux linksys routers and flash with DD-WRT or one of the other open source routers to implement QoS on your home network to prioritize SIP traffic. Our small business used to use an on premises box, but ended up paying the $35/month for a hosted Asterisk VM at lylix.net right on the internet backbone, and it has been practically bulletproof for the last year and reduced a lot of the hassles of hosting our own.

Just food for thought...