For that purpose it's hard to beat a shelled micropile like the Rab Vapour-Rise Light or Marmot DriClime. They are excellent pieces for keeping a comfortable microclimate next to skin and dry SUPER fast. The Driclime is cheaper and functionally about the same so you might want to go that route to try it and see if it fits your clothing system.
On trips where it's when, not if, I will get wet I live in my vapour rise lite. I've had one to the top of Rainier and on nearly all of my hunts.
