It just occurred to me, while I was thinking about the WIFI system that the Solo uses, that it might be possible to use a strategically placed, battery powered, WIFI access point (or points) to increase the range of the Solo. You would likely have to reprogram the solo and controller to connect to each connect to a third device (really fourth if you count the phone/tablet). But if it could be programmed, then you could place one, or more AP's--each within range of the controller--that would allow the Solo to jump to the strongest signal. The AP's could be standard WIFI routers with a third party firmware, and I doubt that they would need much extra programming to work with the network.
You could take it 1 step further and use multiple Solo's in the same network, though the bandwidth might become an issue then.
You could take it 1 step further and use multiple Solo's in the same network, though the bandwidth might become an issue then.