55.2-59 59 Rear brakes

[Dyslexic Dog]

Ugh, I bought and am installing a Must. II 5 bolt 4 3/4 front discs. I would like to go to the same on the rear end but with the emergency brakes. Classic doesn't have one, and the front cannot be changed to the existing 6 bolt pattern.

So, what are my options other than having two different wheel patterns? New rear axle? What kind should I look for? Can I stay with drums and have the axle rebuilt to a 5 bolt pattern? Any help is appreciated. Short box side step 59