I'm heading off on a one-man doc trip. Audio is a Zoom with NTG-2 on a miniboom and a wired lav.
I can't afford a wireless setup that compares to the lav I've got, BUT I wonder: possible to add a bluetooth transmitter to the Zoom to monitor through an Android phone and just put the Zoom on the subject's body? That could be a cool setup.
Also check some wireless audio thing (made for players). It works like blootooth, but with better range and better quality. I completely forgot how it is called. Research ebay and tell me if you find it.
I have tried some bluetooth transmitters a while ago, but was not satisfied with the quality and especially not with the range.
I would say forget about it... either use a direct recording without any wireless, or if you have to go wireless, then spend money on something that just works - Sennheiser for example.