If you are going up the porting may need to be changed.
I was talking with AOA, not to long ago, about what it would take to make my .22 RedWolf into a .25. The items you have mentioned as well as possible porting was the answer I got. Though if I were to go down in caliber size it would be much easier. Then it would just be the above parts, and some tweaking of the Heliboard.