I have a spare xr lower that I'm trying to sell for $2000. But I have basically no takers.

Is it possible to take the guts out of this XR lower and use them in an SC lower if I buy just a case? 1.25 prop shaft. 1.5 gears. Maybe a different length vertical shaft may be needed I suppose, anything else?

Yes you can use your bravo stuff and put in the sc standard length case if you go -1" or 2" you need a shorter vertical shaft , just like you thought