Mitutoyo 104 Series Micrometer - Have you seen this tool? 

When I saw the title, kinda thought what's the big deal? I have big mics, too. Now I see what it does and want one of these, as well. Going to keep an eye out. Definitely a very cool tool.

I just picked one of these up with all the anvils for $15 USD. The box is junk, but the rest it in great shape.

It's good if you only need to measure rarely in the bigger sizes. I have 200-300 and 300-400. Smaller ones I have individually