I've built and am building 3 17" jumbos. Two are based on a Washburn "Prairie State" that I made a mold for from luthiercooltools instructions that included 15' and 28' radius dishes. Got the bracing scheme off the Washburn using the inside/outside magnet trick for a template pattern. (Sorry Haans, not very Larson traditional). One is EIR/Sitka and almost finished with a Maple/Sitka.

The other is a J200 shape using the LMII plan drawn by Rick Micheletti.

The Prairie State Does not have a boomy bass and is fairly balanced across its range. Not sure what you mean by "tight".

Here's a pic... Was gonna call it "Mae West" for the big bottom, narrow waist. I like the slope shoulders.

Well Carl, I was surprised to find that Washburn (modern) had attempted a "Prairie State". I had built two 17" red spruce/maple and 4-5 16" with the short 22" scale. They all sounded VG but I preferred the 16" because of the very short scale and big sound. None of mine had whatever bracing Larsons used on the PS. Instead, I used a combination of X bracing and ladder bracing with laminated braces. The all sounded just fine and quite even. Here's a few photos. Never did get a full shot of the 17" but some of the construction photos are still around...

Funny, I used to call the 17" "Big Bimbo". I'd say unless you have plenty of bucks for custom cases. stick to a standard size jumbo...

Nope, they are either BRW or Wenge. Never liked to use anything but wood in acoustic parts.
Thanks Dan, I did make a number of 16", but never thought of them as "Jumbos". I thought them to be more of a real guitar compared to the tiny taylor toy. I called them mini-jumbos. Charlie Hoffman called them the "perfect old man's guitar".