Burton, I'll have to check out the Reevu when I get a chance....but I have a good helmet, and spending several hundred dollars for a new one when my old one is perfectly good seems a pricey way to go, especially if the helmet doesn't fit my head well (I have a Shoei head).
ut-zero, I've driven RVs with the backup monitors and they're terrific. After a recent experience, I got back on my bike and started wondering if there was a better way than staring at my elbows. This thing looks pretty close to what I want:
http://www.amazon.com/gp/product/B00L0FKHCU/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1but I'm a little reluctant to order from an obviously out-of-country supplier with no reviews, especially when I'm not sure it'll do what I want. I'm trying to figure out right now if I can create an "ad hoc" WiFi network to connect to it with my phone, without paying AT&T extra so I can use their hotspot firmware which I don't need, or rooting my phone if I can avoid it. The USB interface is also a possibility, since I'll need to hook it up anyhow for power, but there's no guarantee it'll send live imagery over the USB port. And of course they DO claim to have an Adroid app, but god only knows if that's any good!