Has anyone any experience with those tank bags that are specifically designed to hold a GPS? If so would you recommend them? I have an older automotive Tom Tom that I'm thinking of using in one of these bags. I don't want to drop $700 on a motorcycle gps. There's some speculation that Garmin may be developing a new GPS that incorporates a lot of the technology developed for tablets. Id like to wait and see if that is the case. Or if I could find a Zumo 220 I'd consider that as an option. Thoughts?