I still can't recommend the db4lw enough as a wireless unit. Massive LCD display with massive digits, multi-line display... and CHEAP.
$22 CDN at MEC.
http://www.mec.ca/Products/product_d...Eprd_id=748239
I would only buy a better comp if it had wireless cadence as well. But I don't need cadence so.
* something that shows up at night
You can get clamp on led snake style lights for that
* waterproof of course
Most if not all already are.
* on-board bell or horn
Seperate loud ass ringer is about $2.
As Late said depends on how well YOU calibrate it for your own setup. They're essentially the exact same thing on every bike comp, some display more decimal places. Db4lw reports down to the meter
* reports rear cassette gear
No idea why you need this...