Imagine the crater encrusted battlefields of DUST 514, its players building, buying, and destroying combat gear whose properties and appearance were decided by EVE Online's players. Imagine if pod pilots could invest their energies into concocting new and devious combinations of machinery in a deep, complex development system to give rise to new war machinery for purchase by the mercenaries fighting across New Eden's worlds.
I've always wanted a hardcore engineering mode for the creation of new ships in Eve Online, but implementing the dynamic in DUST 514 is a fantastic proposition to me. If Eve players could offer equipment for the DUST bunnies to purchase, using a variant of the game engine technology that lets you make Tech 3 ships for player designed ground equipment, the interaction of the two games could become even more interesting, creating a whole new level of interplay, while creating a great incentive for more DUST players to begin playing EVE Online.
It would probably be hard as hell to actually make happen, but damn if it wouldn't be sweet.