Wow! Thanks for the quick [and helpful] suggestions. I'm aware of the El Whappo Grande and the Bag End Infra/Elf systems, but never actually heard from anyone who owned played through one.
I did see the low F# on the Conklin basses, but again, haven't talked with anyone about its practicality.
I probably will rarely hit the F#, but a Bb and an A would often be useful, especially as they would then appear further up the neck. I typically play there.
Besides, just imagine how many people in church would think they heard from God!