There's an outfit locally that tailors to ag repairs, and they can fill tires with foam.
It takes 3 days to fill and cure a tractor tire with a hard foam that completely fills the tire and wheel groove.
End result is a tire that doesn't need any air pressure to handle its max rated weight, and is impervious to punctures regardless of size.
Best part of it is the foam hardly adds any weight to the tire and will last longer than the tire carcass.
Bad part is that you have to cut the tire off the wheel when you wear your tread off.
I've been filling my tail wheel tires like that for years, and since its a two piece wheel I don't have to cut the tire off to replace it.
Doesn't cost that much to do (costs me $40), especially when a new tube costs $65.
They even have different density foam for different tire profiles...so if you need your tire to squat they'll add low density foam.
High density goes up to a 60psi equivalent, low density goes down to 4psi, and they can mix it anywhere in between those figures (also depends on tire profile).
It doesn't work worth a damn after a long burnout though...the foam eventually melts and leaves an air gap around the inner surface of the tire.