Yes, the new Brodak B-25 is a great new offering and one that I've been watching for some time. Designed by Pete Klepsic it's a very nice design but has an asymmetrical airfoil and is primarily intended as a profile scale model. I wouldn't really consider it in the same "market" as a stunt design would be. I'm also familiar with the Twin Mustang being very different from "two" Mustangs stuck together. Coincidentally, I've actually got some original F-82 drawings that I did myself a few years ago that are nearly identical to what Pat is showing here.
With the following, I'm not trying to describe a hard-core competition model, just a nice scale appearing plane with good stunt capability. I know much of this is probably already realized, but I'm just going to "think out loud" for a bit here if I may. With Pat's F-82, simply giving it the symmetrical airfoil automatically opens up many more flying options. The design has an excellent scale appearance, but as a bonus it would also have some decent stunt potential as Pat's designed it here. The incorporated dihedral will also help the leadout/vertical CG relationship, aiding even more to the potential stuntability. I am very confident that this F-82 design, built at a decent weight and with good power, would suprise many fliers with it's stunt capabilities. I'd suggest a little more wing area, but we'll get to that.
Below is another slightly different approach to design, but one that definitely works. The approach is also nothing really new, but is proven.
I'll roughly describe my hypothetical B-25 design here. This is how I designed and built my 64" PBY Catalina stunt model...
Depending on the chosen full scale subject there will always be slightly different ways to modify and end up with the desired result. While designing think
scale, but pay very close attention to the "stunt devil" sitting on your shoulder and let him influence things all the way through.
Starting with a "clean sheet" stick diligently with true to scale outlines but play with size relationships between various components. First, pick a desired wingspan, say 56", and print off an enlarged full size scale three-view at that dimension. Be sure to start with a detailed, quality three-view, like on the order of a Paul Matt drawing or similar. Save and set aside the fuselage outline as is. Then, in the case of the B-25, "cheat" or add to the overall wing chord slightly, including the flaps. This is to sneak in some additional wing area but you want to stop before taking away noticably from the scale outline or appearance. Do the same with the stab/elevator and also add in a little more span, essentially you're just enlarging the entire stab/elevator assembly.
Now, take a clean sheet of paper, draw a long horizontal line and mark in the desired moments using the "new" wing/flap/stab/elevator chord dimensions. Take your saved scale fuse outline and lay over it. You will likely need to adjust the fuselage length to fit things where you want them, just make adjustments for the best overall scale appearance/stunt compromise.
At this point thrust lines and wing/stab height relationships can also be subtley adjusted without detracting from the scale appearance. You may find that you'll want to "section" some height out of the fuselage outline, or not. Go for it if necessary, but keep the top and bottom outlines true to scale. Spend good time getting the fuse proportions just right in comparison to the flying surfaces to maintain the overall scale look of the model. What you should essentially end up with is a scale fuselage with proportionally larger flying surfaces, all with scale outlines.
This isn't a complete description of the process, but just my own general approach and thought process. It is very possible to design a model that appears very scale but will also be a suprisingly good stunt model. The best of both worlds in my opinion.
(I apologize for getting a little long here Pat. I'm not intending to take away from your F-82, just adding some "food for thought")