Bulb effect research

[Guest]

With an eye toward due diligence, I would like to solicit additional background on the Bill in Light Bulb and Milk in Light Bulb effects.
In the early '90's, Marvyn Roy granted me exclusive rights to produce The Bill in Bulb as designed by and used by him. After several years of production I chose to stop building for a period of time and am now considering re-entry into the field in a limited way. I have contacted Marvyn to confirm that I am indeed still the only manufacturer with his permission and input to build his version of the effect.
He also said that Owen was granted permission to do Milk in Bulb, a similar piece using nearly the same props.
During the time I was on hiatus I became aware of a couple of different "Bill and/or Milk in Bulbs" produced and marketed, which is neither here nor there as far as I'm concerned. My question is, does anybody have any versions of the genesis of these two effects?
Certainly, the Canary in Bulb via Les Levante, Horace Marshall and U.F. Grant as well as Milk in Bulb as made by Max Londono have contributed to Marvyn Roy's effect but as near as I can tell, in this generation Marvyn's permission is all I need to retain. Anybody else have other threads I need to look into?
Oh, and to prevent any snarky comments, this is not the sum total of my research. It just seems like magic bulletin boards should be a logical place to help fill in gaps.