Sure it can be done, there are lots of SMPS controllers which can operate as low as 0.8V in. You can use one to make a low-power auxiliary supply voltage, maybe 5-15V, which can then be used to power a separate high power converter. Doing the step up in two stages is probably a good idea. Maybe you can convert to 12V, then use a car inverter from there to make things simple.
The most difficult part will probably be the first high power conversion stage. You'll need inductors and FETs with very low ESR, like in the milliohm range.