...I fail to see where it would be better for a layman to build a car from scratch for electric power over converting an Insight. Any other car yes but the Insight has all the needed requirements for an efficient electric conversion.
Without question an Insight shell has a lot going for it, inlcuding but not limited to the alluminum material as well as the aerodynamic form if as you say, a layman were interested in converting it to a full EV but I suspect that the layman, when he/she completed the work, they'd be less than satisfied, dollar wise and other wise.
It's the cost to do it and do it right to which I call your attention. If you've never seen a set of those Reily plans I mentioned, do get a set. Get what he calls the URBA CAR or the URBA ELECTRIC, better yet, get both sets. Both are from "scratch" vehicles. The former is NOT intended to be an EV, rather a 50MPG ICE powered, two seater, with gull wing doors, but one easily adapted to be a one hundred percent EV. The body styles are completely different but the basics of construction is identical; tube frames, plywood and fiberglass.
As for the instrumentation, that which is in the Insight is unique to that specific class vehicle. If you're going to convert it (or any other vehicle for that matter) to an EV part of your budget should include the appropriate instrumention, which is available by way of the multitude of firms offering EV converstion kits - or elsewhere, just as they offer electric powered vacuum pumps to operate the vehicle's brakes. Trying to adapt the Insight's electrical system to perform as a fully functional EV machine will in all probabilty prove to be a proverbial nightmare for the layman.
For the average layman (like me) it is to the total costs involved to which I draw your attention. Until I leanred of the Insight, I was gearing up to build the URBA CAR - as an EV. I had gone so far as to acquire the plans (also purchased the Urba Electric plan set) and using carboard, choosing the metric (CM) scale as opposed to the foot and inches (i.e., 12" = 12cm) as shown in the plans, I'd cut out just about all the parts needed for assembly to see how they'd fit. While doing this, while reviewing the cost schedule for the umteenth time before committing to a full scale construction project, the total cost (parts, labor, material and licensiing) came to just over ten thousand dollars - then on eBay I spotted a new Insight for sale in New York and they were only asking some seventeen thousand dollars for it! That Insight came with more "bells, whistles and chrome" than my Urba EV would have had. For me, it wasn't all that difficult a choice.
You might note that I am not the greatest body man or mechanic you'll ever meet but over the years, while an amateur, I've done my share of such work and I can offer that if you believe the layman is going to save money and time by converting an Insight shell to a full EV and end up with essentially a fully functioning Electric Insight, experience tells me this isn't going to happen. There's no question it would be a labor of love but for the costs, without question I suspect that the results will be very disappointing for the average layman.
Hope that answers your question.
Fred / Proud Owner of "The Silver Bullet"