There are a LOT of dual point SBC distributors out there, so trying to "jury-rig" a second set of points into a single point distributor doesn't make a lot of sense.
Please excuse me if I didn't understand your question correctly.
Of course, I should really be encouraging this sort of thing, because if someone does it, they will have to remove the condenser from inside if the distributor to make room for the second set of points. Then, they become a potential buyer for one of my "Trash Can" condensers.
(Nothing looks worse than a stock condenser hanging off the outside of a "hi-performance" distributor.)