Large fish don't transplant well. The new environment often causes them to languish, drop weight and die off.
I've often thought that finding a huge female on a nest, running her off, getting the eggs and hatching them would be the way to go. However, every step of the process would be problematical.
I bet some commercial hatcheries have done it.
You might be better off buying from a really good hatchery and throwing lots of food in there.
All you would need is for the fish to survive for one spawn. I understand it would be difficult, but if the state of Texas can do it on a pretty large scale, I am sue it can be done.
It is a shame the Texas Lunker Share program doesn't sell any fry. I am sure they could make an absolute killing.