Had a couple guys in my class at Spirit that were part 91/135 only, as well as some pilot's that had only light twin time flying for 135 outfit with no jet time. So yes it can be done, and I wouldn't be surprised if this trend continues as major's continue to retire pilots and the demand starts applying pressure on the regionals. My understanding is the big 6 and ULCC'S will require close to 7000 pilots hired this year, and that trend will be continuing for quite some time.

The majority of my career was part 91, with a brief stint in 121. Flying for regional was good experience, but I'm glad to be done with it.