Good idea, or, just not willing to commit?
I learned about Musical Designs tube preamp the Camileon. What caught my interest was the fact that you can change circuit boards in this preamp. For example, one board uses a single 6922 where another uses two 12AU7. You can even select feedback or no feedback. There could be others but that's all I heard about.
John Hillig is the man behind Musical Designs. Apparently, he got started back around 79 doing mods to other brand amps. Now he is putting out some gear of his own.
So thoughts on being able to swap boards in your preamp?