Henrik, try the burton 250 kw engine.
. I am afraid you loose the trunk then for some space.
You don't think. that if you build a 1 to 3 kw engine your range will be very limited?
Maybe take a look at quasimodos site
www.sinclairc5.nl. he is in the proces of building a 750 watt version.
Where are you in Denmark, I'll visit the Skive Viborg area next year.
greetz, Med venlig hilsen
Frank