need some help with making a brushless LST

[honda237]

so i finally couldn't help myself and i am going to make a brushless lst. Here is the roller i won, pretty nice huh:
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT

These is what i am going to use:
Motor:
mamba monster 2200Kv system
battery:
zippy 5s 5000mah 30c lipo
other parts
The dudes motor mount & single speed hub
traxxas 2.4ghz radio, and emaxx receiver box
rc-monster pinion and battery box(50X150)
Servos 2 Jr z590

Desired speed 40 mph

My questions:
What size pinion should i run?
What are my runtime looking like? Estimate
Is my desired speed sound realistic, with out over working the motor?
Anything else i am missing?
Any help would be great.