When it comes to the ukulele, I've been pretty much a traditionalist in terms of tuning. I had tried some low-G tuning, but currently every one of my ukes is tuned re-entrant C (GCEA). I guess part of it is because all the songs I know uses re-entrant tuning, but for some reason I've been reluctant to learn more low-G songs.
A couple of days ago someone at Ukulele Underground asked me to try tuning my Koa Works tenor to EAC#F#. He also owns a Koa Works and found this tuning to bring the best out of the ukulele. I figured I'd give it a shot and tuned the Koa Works down to EAC#F#. I liked what I heard but because the Koa Works already has pretty low string tension and very low playing action, the strings felt too loose and slappy. I thought perhaps the 18" scale on my William King tenor would handle this tuning better, and sure enough, it gave about the same sound without the loose strings of the Koa Works tenor.
This tuning made the King tenor sound like a mini-guitar. There is more sustain and more warmth to the sound. I thought it sounded pretty cool. The person who referred this tuning to me said he tries to tune many of his ukuleles (he has more than I do!) with a tuning that maximizes the potential of the particular ukulele. I don't think I know enough about sounds to do something like that, but I think I'll be experimenting with a couple of my ukes for sure. It's pretty cool to hear a different character from ukes you've played for a while.
I just learned the Beatles' Imagine as played by Aldrine Guerrero from Dominator's tabs, and I thought this song worked pretty well with this tuning. So I shot a quick video of it this morning. I only had time for about 2 takes and I was far from perfect (as usual), but maybe this will give you some idea what EAC#F# sounds like. Try it at home today!