Mine isn't custom, but I'll not buy another ML unless someone improves drastically over my Savage 10ML-II. I'm as confident with it as I am my 7MM Rem Mag within 200 yards and I've never had to tinker with it. The suggested powder/primer/bullet/sabot combo has proven to be the ticket for mine right outta the box.
Cheapest way to get in the game is to buy used or build a conversion on an encore frame. If you have an encore you can buy a 45 cal Brux Barrel ready to go from smokelessmz.com. Luke is a good guy. I know where a 40 cal built on a rem 700 action is at local for $1100 If interested.