Ya kenna beat the laws of physicks, Cap'n, and ya kenna beat the attitude out of some folks... Depending on the day it's amusing, boring or maddening... It's certainly a suitable topic for the DB side of the board as the guy is asking how to make something sound like a DB. Even if the answer is "forget about it", what's the problem?
My position, based on experience? ABGs blow big chunks for the most part. For a long time I avoided this conclusion, but alas, there it is. My thang has always been how unloud and unfocused their sound is, and if you plug them in, they sound like EBs with feedback problems. Acoustically they get lost in a lively jam with fiddles and banjos and other loud things. As for making them sound like a DB well, that's why I play DB, not ABG.
To add a new wrinkle to the thread: in looking at the whole ABG thing some years ago, I found a guy on the web (and have since lost the reference -- hard drive crash; he was in Arizona or New Mexico or someplace southwest) who was making long-scale archtop ABGs. Or at least he had made one of them. He was using Lee Sklar to help sell them. I haven't heard the instrument (which looked gorgeous), but it seems to me that with a 36 or 37 inch string length, flat wound strings and good wood nicely carved you might be getting somewhere close to DB-ish sound approximation. Frets are unthinkable, of course.
I think, though, the farther you go down the long-scale archtop road, the more you wind up with a design that approaches the bass violin in terms of sound and cost to execute.
So why bother with the ABG quest? Because they would be a lot more convenient to carry around than a DB ever would be. That's why the interest in the possibility will never go away...