I don't know of any small distillers that you could take backpacking, but I bought this self assembly distiller:

http://www.conquestinc.com/lifesaverdistiller.htm

It works, but the plastic hose makes the distilled water taste like crapola. The "food grade" hose may be safe with food/water, but it can't handle the heat. I guess I need some copper hose, but haven't followed thru on that yet.