It's not the outside the framesaver is for but the inside. I have to do this for my new Salsa Vaya which will be my new do-all bike...40 mile round trip commuter, kid hauler, etc. It has pretty much everything your looking for but for slightly more($1500). I was checking out the Cross Check and the Long Haul Trucker but liked the 26" wheels offer on my sized frame plus the sloping top tube.

Now for building something up yourself doesn't have to expensive also. Does your area have a larger bike community or larger bike section in CL? Also don't forget if you plan on building it yourself you'll be needing some specific tools to install the bottom bracket, headset(debatable), cassette on your hub, chainbreaker, torx bits for the rotors sometimes. Though you can buy a tool kit from nasbar for just around 100 and it has pretty much everything you'll need.

As for a frame with disc mount I would also check out the Nasbar steel or aluminum cx frames.