The aprilia mx 125 has them as standard. f**king hate mine, on my 2nd one now. First one stopped in the wet, never worked since. My second which i got new in September works in the wet, but doesn't give an accurate measurement of speed. I don't think i did 198.2 mph in the wet. They dont light up in the dark, just have a button which lights up the "Back light" for about 5 seconds. Even when i wash my bike the clocks go funny. Just glad im getting rid of it soon.
The vapour is pretty easy to fit, as long as you're good with electrics and can read the instructions. Download them from Trailtechs website so you can familiarise yourself with what's involved in fitting one before it arrives.
It's not plug and play so you'll need to do a bit of head scratching and configuring, especially to get the Speedo working accurately.
Oh yeah, they are around 90 pounds for the unit and a sensor but the sensors are crap that come with it so I had to get a decent one from a company in America that was an extra 60 quid delivered so quite expensive!!