I'd love either of those options, but they are not really options for me. I can't afford a second DB(I wouldn't be able to justify this one save for the fact it was an absolute steal)& although low C would give me plenty of range, the same money excuse goes for an extension. Also, though my bass looks as if it was once dragged behind a truck, I'm keen to preserve it as much as possible. By all accounts it's 60+yrs old- no huge deal, but in the event of a fire, I'd likely grab it just after throwing my 3 children out the nearest window.
Edit: I have considered fifth tuning, & may try it sometime. I'd like to test it out on BG first. Thanks for the replies.