I "mini-carbined" my 1377 back in 2009 and my first 2240 in about 2011. You're right. That 1377 is so, so accurate. As you'll be aware, you have to do your bit.....short barrel, totally standard trigger, very light weight and slippery-in-the-shoulder stock punishes even the slightest lapse in technique. Like a 1" flyer at 10 yards. However, get "in the zone" and get everything just right and it will print 5mm edge to edge groups at 10 yards. Yes, really.
I also have a 2240 and 1377 totally standard. But like to have one in standard guise. I'd love to build a longer barrelled 1377 based carbine, too. Or, maybe, a 2250 with steel breech but convert to .177. Once things get back to some sort of normality I ought to look at selling my least favourite gun (a Mercury) and embark on another Crosman mini-carbine project.