Richmond is out of business and the parts for the Nash 5spd / ROD are hard to get these days, depending on who and where you are. The TKO is quickly becoming obsolete, and many parts have been discontinued. That leaves you with one of these Keisler LGT 5speeds. Apparently they arent shipping those yet..Im not in the loop on that stuff though.
How about a 4 gear solution for you; 2.98 1st gear in your Muncie and 3.08s in the back end. 9:1 total gear reduction, economy of the 3.08s; no shifter mounting woes, no swapping clutches or driveshafts and M22 strength.
If the 3.42 in 4th gear doesn't bug you; get an M22W gearset. M22 Rockcrusher strength with a 2.5x 1st gear. Its a help in 1st gear.
If you're really on a budget, you could change the input and cluster in your M21 to M20 units, get the same approx. ratio as the M22W without the strength increase.