Anyone looking into a lightweight EV should consider quad bike parts. Try Andy Noble on
www.andynoble.com he is very helpful and has a plethora of salvage parts. I got the front end of a Kwak KLF300 for £200 inc wishbones, dics and calipers. For the back of a trike you could consider a Peugot speedfighter scooter front fork with its leading arm suspension and disc and caliper, absolutely perfect as a trailing arm. Nearly all scooter used parts firms have these as its one of the most common on the road. For motor kits try
www.electricmotorsport.com a very informative site and a good range of smaller kits and good prices. Have fun building or just thinking about building an EV.