Sounds an interesting project.
Your best bet might be a PM DC motor, as these will give plenty of power for this size project and have readily available controllers.
You could go for a high performance motor, like the Agni (see:http://www.agnimotors.com/home/
) or perhaps the Perm (see:http://www.perm-motor.de/index_en.php
) or you could opt for a much cheaper (but heavier and slightly less efficient) Mars motor (see:http://www.marselectricllc.com/
). Mars also do a brushless version that might be worth considering.
Controllers for these motors are readily available from several companies. Alltrax and Curtiss are both well known and have been around a fair while (see: http://www.alltraxinc.com/
) but a newer supplier worth looking at is Kelly (see: http://www.kellycontroller.com/shop/
A bit of time spent Googling will soon find vendors for these parts and allow price/performance comparison. Other parts, like contactors and throttles can be found on the sites of the vendors that sell motors and controllers usually, although it's worth looking on eBay once you have decided what you want.
Batteries are a whole topic on themselves, with lead acid being fairly easy to buy in the UK, relatively cheap but giving only modest performance. For best weight/performance it's hard to beat LiFePO4 cells, but these are more expensive, need battery management and nearly always need to be imported from the Far East.
Hope this helps.
A quick Google