GWH77,
The North end of the Bridgers used to hold lots of huge mule deer. My friends grandfather (died at 104 years of age about 5 years ago!!) has a picture of a Bridger canyon mulie hanging off of both sides of the back of his surplus jeep. Very nice rack (he still had it) and rediculously massive body. Never seen anything like it anywhere. Those were the days...
Before the land trade with the Forest Service and the lumber company/Yellowstone Club there were nice mulies to be had up Pony Creek/Skunk Creek/Flathead Pass. They are certainly still up there, just harder to find and fewer of them. Mulies don't handle the stress of starter castles up in the foot hills as well as the white tail do. More houses up in mulie country = fewer mulies.
With the mild winters lately you might want to try some off-logging-road areas up Gallatin Canyon. Lots of people after elk, not as many after deer. The North end of the Crazies is worth a try.
I've been in Bozeman for a bit over 20 years and look for bigger mulies East (way east) of here.
Good luck!