Have you given the Velec's a thought? The 36V A2 Model comes in around 40 pounds and I bought my wife's brand new last year for $1700 plus tax here in Eastern Ontario. Head office is in Quebec and parts usually arrive the next day. They also make a 36V foldable bike which may suit your needs. Its the Velec RX36. I'm not sure of the weight or cost but it may be worth a look. I have a Velec R48V which I love. However it's over 40 pounds and over $2,000 CAD. But good luck in your search. That's half the fun.

Mike