I tried the Takamine out in a shop in London earlier this year. I didn't like it as much as I wanted to. The fingerboard was too radiused, it balanced poorly and the scale length, at 34", was too short for what the instrument is trying to achieve, IMO. Instead of ending up with the best of both worlds, it ended up being the worst of both worlds. I was really bummed out because I thought it would be amazing.
I've never seen the Landscape ARB-204/FL in person, but I'd be more than willing to check one out next time I'm in Tokyo - whenever the heck that'll be! The price is certainly reasonable. It looks like it would be a better attempt at what the Takamine was trying to do - then again, I was already let down once.
I found that the Corellis respond really radically to string height. ...on a DB, at least. A fairly small increase in string height resulted in a big increase in volume and digging in just a bit made it distinctly less delicate. Don't know what the results will be like on the world's biggest ukelele you got there, though.
Manage to get the Hohner before closing time?