If you can make do with 1.8 A you could use a Lazeerer X-boost. His more powerful driver the Super-X-Boost (SXB) unfortunately won't fit.
I know people have also used Lavas flex drive in parallel (buck/boost driver) with success, so you might also be able to do this with two X-boosts running at identical currents. Two rectangular ones will just fit in, but you won't have much room for heat sinking the drivers.:beer: