Don't know if you guy's know the brand Robitronic
You should know it from their REAL
They've got an great speedo: iCUBE it's called
About the size of the Novak GTX
It has some really great features, not just 'auto break' but also 'auto roll'
it has a great data recorder wich you can download to your computer like: voltage, current,power, impedance, throllte and time.
Real good to analize where you keep loosing those tenth's during a lap
Don't know if it is available in the US, you might try to get one via european postorder or maybe somewhere in asia. But please pay attention to the currency exchange factor. buying in euro's mean paying big $$
In Europe it costs about 170 Euro's about 220 US$
But all Big brands have a great speedo in their package Novak, Ko Propo (and all it's spin offs), LRP, just to name some......
All the best !