I owned an XB-40 back in the day. It was a big chunky thing. I didn’t end up loving it in the long run. Not surprised they discontinued it.
I tried Brendan Power’s slip-slider harmonica recently, but it lacked the responsiveness I need to feel happy.
Perhaps his PowerBender or PowerDraw harps would be appealing? I just got one, but haven’t given it a real test drive yet.
You might enjoy taking a dive down the rabbit hole of the alternate tunings forum post.