Actually was one of the "digs" that metric motojournalists did not like about Harley "controls" using two thumbswitches, no self canceling ("big" feature of all the "clones"...in the 70's), HD waited till electronic iginition came out in conjunction with the "bank sensor" to do theirs, as most metrics had "patented" their ideas...I think).
And yes, the aftermarket has kits, like Opaka Lips refers to as a DIYer mod. Might have to Google it to find it, is similar to windshield wiper delay timer ckt...