I had this idea that there should be an advanced naval unit that carries land units across water, and maybe also a more fast, but expensive carrier that flies. Just and idea i had also, still waiting on that texture not loading on planets for mac users with AMD's
I imagine there will be various forms of transports. They've mentioned in the streams that transports are difficult code wise, so they are working on them. So there will be transports that can carry units across water or crevices in one way or another.
a surfboard-like unit would be an interesting twist on naval transport. something like this http://zero-k.info/Static/UnitGuide#unit-Surfboard