With 2WD its not so compelling to have a lead on the hack wheel. The WWII Norton Big4 military outfits had tug-rear and hack wheel in line.
Its a lot to do with where the combination C.O.G. sits.
Consider this- its quite feasible to employ a complete transaxle+gearbox from a rear-wheel drive automobile. Since solo BMWs have had VW aircooled boxer fours coupled up to their existing transmissions ---- the reverse must also be possible: coupling a late-model BMW oilhead motor onto a beetle (or kombi) transmission!
Use this for simple 2WD, and modify to produce un-equal drive power-split like 65% Tug & 35% Hack.
Even a complete buggy rear frame could be attached to a motorcycle front end!
Boxer twins are a very versatile design! They've even appeared as Two-Strokes.