Starting my evaluation of the Wilson Mobile 4G, I found an answer from Wilson Tech Support in the Q&A section of the web site about future antenna options:
"The kit that will be made with the RV antenna and the more powerful indoor antenna will be coming out, but not until the fourth quarter this year (2014)."
I am hoping that these antennas will be available as upgrades to users who want them, without needing to buy a full kit. I will try to get an answer from Wilson about this.
The documentation that comes with the Mobile 4G makes strong assumptions that the device will be installed in a car - a much different installation environment than an RV. I can certainly imagine better antenna options.
I'll keep sharing more as I continue diving into the device.
Q&A was found here:
http://www.wilsonelectronics.com/store/display/245/38/mobile-4g