Originally Posted by CrimsonEclipse

Shortened the lower cage.
The upper end allows clearance of all gears up to just barely 50t.
I might have been able to remove another .5" from the lower cage but I don't think it would have made any more difference.
The mod also gave me additional tire and wheel clearance.

My options included leaving material to bend around or remove metal between the idler cogs.
Frankly, I used the old derailleurs with exposed cogs way back in the day and never had a problem so I took the easiest to path to modification.
Drill each side, add threads to one side, cut off the extra material, file to shape, go for a ride.

Today's test ride on gravel and big roots resulted in no mis shifts, chain drops, or other problems. And I wasn't gentle.

So that's it, my $40ish mod to 11-50T
No front derailleur, no internal hub, no new cables.

It'll be my backup bike for the foreseeable future.