>>I'm not sure what the standard tuning for baritone guitars is supposed to be. There seem to be more of them in the US than the UK. (at least, acoustic ones, anyway)<<

I play (around with) a baritone acoustic made by Ovation. Most folks drop them down to either A or B. I prefer the former myself.

Incidentally, Gold Tone's 'bass banjo' uses the same 32 inch scale as a long-neck but with heavier strings tuned down to bass guitar standards.