I just tripped across another source of track roller lubricant.
Chevron MultiFak EP
This is a Lithium thickened grease available from 000 thru 2. For rollers, number 0 is what to use.
Of course, this is pretty much the same as JD Corn Head grease. But, maybe someone has a Chevron lube dealer which is handier than a JD Ag Dealer.
I found it after tripping across a conversion chart for Kendall lubricants (most of which I am familiar with from when we had our tractor shops). Kendall's was L-406.
The chart crossed L-406 to Chevron Dura-Lith, which has had a name change to MultiFak.
Actually, any make of Lithium-thickened number 0 grease would be the same as the original Track and Roller Lube. The problem is finding a convenient source of it these days. Most places only carry number 2, usually with several different thickeners, but number 0 is harder to come by.
The key to number 0 is that is stays put like a grease when idle, yet flows like a gear oil when under motion and/or pressure. Just what we want in rollers.

Stan