Lengthening the bushing puller as you described would work.
But I would call the bushing puller folks first, because they may have run into this situation before.
They might have a solution that we can't think of.
You could make a deal with them, where you send them the regular bushing puller that you have,
and they make you a longer bushing puller for a few bucks more than the cost of the regular bushing puller.
The worst thing they can say is no,
klhansen,Has a good idea with the threads on the end of a pipe, the only problem is,
threading into the brass bushing might be all that comes out. Leaving just the bushing housing.
Picture of an original front bushingIf that is what happens repeat the same thing to the bushing housing.
But I think it will work on the first try.