What type of outdoor breaker/disconnect for two buildings?
Well, you didn't say what your service is.  Whether it's 320 Class service (400A; 320A continuous) or whether it'll be 200A.  Your breaker requirements will be slightly different depending.  

But what you're looking for is straightforward enough: It's called a Meter-main.  Some of them are simply a meter and a main breaker - in separate compartments so the power company can stick their seal on their side.  

Some of them get more sophisticated, and give you a meter, a main breaker and 2-8 breaker spaces on the downline side of the main breaker.  

For a Class 320 service, I'm not sure how meter-mains handle it; I've never seen a 400A breaker; they usually provision 400A service by splitting it to two 200A main panels.  So sadly, you may wind up with 3 boxes in that case.  Think about if you want any power here at this location; if so, look at a meter-main with extra spaces for one of the circuits. 

Fork it

If your service is 200A, there is nothing wrong with fitting dual lugs (or splitting with Polaris connectors) and sending full 200A to both house and shop that they effectively share.  The split is after the main breaker, of course.  

By the way, your wire only has to handle 83% of the breakered value, so only 166A. 4/0 Aluminum will be just fine.  (DO NOT use copper for long feeder like this; it's a total waste of money and the lugs on both ends are aluminum, so you'll create a dissimilar metal problem.)  What's even sadder is when people spend a fortune on copper, and then chintz out on conduit, ground wires or panel spaces.   2 years later, they're back going "panel is full" and the photo shows they could have fit a much larger panel for $40 more, and they wasted $700 on copper feeder. Talk about false economies!