One of their maybe-when-we-get-ambitious goals is double-sided printing, with a camera for alignment... but...
A less-ambitious goal is a non-conductive ink cartridge for silkscreen. And: the FAQ says they're working on multilayer.
Why double-sided, anyway? With additive manufacturing, why not include a (high-capacity) insulating ink cartridge for soldermask and insulating layers (maybe in addition to the different-colored one for silkscreen), and do multiwire?
Multiwire wouldn't be good for RF, absent some way of controlling impedances (which could, I suppose, be arranged, even to the extent of printing coaxial cables), nor would it match the characteristics of normal production boards, but 'twould allow quick few-offs of insanely complex designs.