Not sure what you are trying to achieve here that needs a radio mic?  Could you not use a self contained digital recorder, i.e. the circa £40 Olympus, running alongside your camera for later mixing? Being digital you should have no difficulty in syncing on the timeline when editing...and at far less cost?   Though, for what it's worth, if you want video why not invest in a video camera? Prices have never been better and you cold extend your mic lead to quite a distance. Radio mics are problematical at best and always expensive.   I am producing not-for-profit video to pro standards using a ten year old Sony PC110 and a 2008 Sony HDV cam, editing on Premiere Elements 7 on a laptop to DVD standards.