I see that $55 will get me a Bosch bit that is specifically designed for cutting rebar, and fits in the hammer drill:
The idea seems to be that you use the usual masonry bits until you hit steel, use these bits to cut the steel, then resume with your usual bits. Interesting.
Has anyone used them?
A 1-1/8 bit ought to fit neatly into the hole you're making for 3/4" pipe. Looks promising.
For larger holes - my current project involves 3" pipe - I bet you can make smaller holes to the side of the main hole, cut the rebar, then break it out. Maybe. If you're going to do that, you probably want to remember that most rebar you'll find in block walls is about 3/8" diameter; maybe a smaller bit is in order.
I don't object to renting tools - core drills, btw, are also rented by Home Depot - but there is a time penalty. This job is just outside Memphis, so rental access is no problem.