Found the gizmos at Keystone Country Store, Ten Point accesories (sent you PM hotburn, can't cut and paste here).
I'm shooting the Parker Terminator and Excal Vortex and have four makes of bolts for now; they use different nocks of two diameters (Of course!)
But, being the tinkerer that I am, a plan hatched as I went to bed last night.
Going to cut down several sets of x bow nocks and arrow nock and fasten the two together. They are both hollow inside so a cut down barbed aluminum nail and epoxy will join the two solidly.
It occurred to me that wrapping teflon tape around a long stemmed arrow nock would work too (or Red Geen's solution...Duct Tape).