Out of my league of experience, maybe someone else can respond. Sevcon controllers require complicated programming, however, according to what I've read of Luke's sevcon.
What exactly are you going for in this project? It sounds like you want to get "sort of" into the electric car business, but that you acknowledge it's quite complicated to get really far into it. I'm concerned that you might end up having what amounts to a still rather expensive project, but without the benefit of going all out into the project. You also might underestimate, thinking that a hubmotor project will be easy. It still can be rather complicated.
So laying out why exactly you want this project might be helpful for others and yourself. Maybe a cargo-bike /cargo-trike would suit your interests, and be more likeweight/reasonable.
Here's a tiny cool car: http://www.evalbum.com/3390
. Yeah, i'd also explore those sites to see what other people have done. There might be some way to search the site's car section on google and add the term "hubmotor" or "hub"
New to endless-sphere? Notice a lot of signatures recommending Ebike.ca? That's because it's the best place for a quality and manageable, (but still 'real'), first build. Justin is a solid supporter of electric bike development, and a good source of equipment.
My hat off a thousand times to the green people that effectively run this forum. The ES Mods are superb.