For mine, I went with a Rem 700 action and that's what worked for me. Sure, I wish I could have gone with a full custom, but I'm a medical student at the moment and that wasn't in the cards for me.
I think you've got a pretty solid plan. Just as another suggestion - you could look around for a deal on a 700 ADL package. I found one for $400 cash. Sold the scope, stock, trigger, etc and kept the action and bolt. All in all, I paid $250 for the action and bolt. Not a bad way to start. With the 700 LR, you've got a good stock already, but you might save a bit by going the ADL route (assuming it's cheaper) then purchasing the B&C stock from redhawkrifles.com
Anyways, you're going to really enjoy the Sherman. I've only had mine for a while, but it's been a ton of fun so far.