Thanks 38c.
I did find reference in the archives (12 years ago), to Lovson export's "Super Single". I think this is the whale I was remembering seeing mentioned.
SCL-16; 16hp / 1cyl @ 670rpm 155mm bore X 204mm stroke"SUPER" SINGLE CYLINDER $1,025.00
SCL-20; 20hp / 1cyl @ 750rpm 155mm bore X 204mm stroke"SUPER " SINGLE CYLINDER $1,140.00
SCL-22; 22hp / 1cyl @ 800rpm 155mm bore X 204mm stroke "SUPER " SINGLE CYLINDER $1,160.00
235 c.i.d. (3.85L), 6 1/8" bore, 8" stroke, 300lb. flywheels (x2), one cylinder. I don't see it referenced on Lovson's site anymore, Looks like their top dog is now just the "SLC-12 SUMO"; 1.7liter, 12hp @ 1krpm, 127mm x 139.7mm. I suspect they would/could still deliver the SLC super single upon request.
I also see Topland still offers the "18ADI2" 3.35L 20hp/1cyl, 155mm x 177.8mm, as their heavyweight single.
I'm guessing the Rajkot mfrs aren't selling too many of these bigger units over there, since the India exporters are still overwhelmingly advertising the 8/10/12-1 clones as their lead product.