Tracy, I got some info on this and the 3 state cooperative effort was NLMB and SMB. Ironically they used NLMB from OK and TX. KS used SMB of Erie strain.
This was done last in 2012. It requires 2 locations/rooms to control light/temp. They used Hormones to have fully ripe eggs. They also used hormones on the 36 male SMB to get the timing right.
In 2009 they produced a small number using female SMB and male LMB, I asked why they would go that way if smb produce so few eggs compared to lmb. They were looking at learning to manipulate the fish artificially more than looking for large numbers of reproduction.
This sounds like it was more complex than what I remember but it does require complete separation and conditioning for each species. Even timing of hormones sounds like it was critical-more so than what we do with stripers even.
Tim is sending me a synopsis of the program which will be in great detail but he did say this cross is past tense but they would still allow observation of lmb spawning process.