I wish there was an Axe III "sidecar" unit, maybe only 1 or 2 rack spaces, which could be joined to one's Axe III via a ribbon cable (or however), and which gave you the ability to have a few more rows and columns on the grid, and which gave you enough processing power to have an extra 2 amps, plus extra drives, extra everything that a normal Axe III has, but with only minimal user interface. The "sidecar" would basically operated through the Axe III's front interface, appearing as extra options. It might also offer an extra set of outputs or FX loops (since there's panel space, why not use it?) and, on the front, some extra software knobs. (And of course, it'd cost rather less than the Axe III itself.)
I recognize that the market volume doesn't exist; I recognize that at the small economies-of-scale it'd actually be just as expensive as the Axe III itself; I get the economic reality.
But that's what'd scratch my itch to have 4 amps, plus some other stuff, and is plausible from a technical perspective, and would allow people who don't want the extra power to skip buying the extra power.