Welcome to the forum Andy,

Drive motors - I would recommend drill motors as these come with a suitable gearbox and many ready made mounts and wheels are available via members of the forum. These attach directly to the drill motors and provide lightweight powerful drive units.

speed controllers - There are a number of options available,

- electronize (technobots.co.uk) - Very good controllers with very few problems that will easily handle drill motors (look to the 15A processor controlled units).

-Sabertooth 2x25 speed controller (gimsonrobotics.com) - No experience with these but the specs are very impressive

- robotpower scorpion XL (xbotz.com) - Again I have no experience with these and the specs arent as high as the sabertooth controllers but many robots have been successfully run with them.

With batteries you have a number of options available -

Sealed Lead Acids (around the 2.2 to 3Ah range) - heavy but reliable. Not used in many competitive bots anymore.

nicads - These are better for bursts of current. I use nicads in my spinning disc featherweight and they happily allow 50 to 60 amps draw bursts (they do get quick toasty)

nimh - Better for constant draws however many brands are heading towards being just as good as nicads in terms of burst currents.

lithium technology - I would stay away from this area completely for a new featherweight.

I hope that that helps!