I know Accuride and Alcoa make 22.5" Super Single wheels which I was considering using, but I think I would prefer to run Military Beads for air down and bead retention purposes.
I know FMTV and HEMTT wheels work but I'd prefer not to mess with multi-piece beadlock wheels.
While certainly 20s can be aired down lower than 22.5s, is the difference of 10-15 psi
(no internal beadlocks on one piece 20s that I know of) going to make that big of a difference on your 10 ton 29-foot long truck? You will certainly be more limited by the size and weight of your truck, and the corresponding approach, departure, and breakover angles, than whether you got 150 sq. inches of contact per tire, vs 180 sq, inches per tire.
Most of the FMTV etc wheels would not work in your application as they were all on trucks build as super singles so match axle widths, therefore most are not 'flippable' to swap front to rear on a truck that started life as a dually. Some like the Hutchinson Atlas rims (NSN#2530-01-479-2916) are, but very-very rare (and of course two-piece).
As always YMMV