Great question Ralph... Reading your title, the first thing that crossed my mind was the
Electra Townie Go! but you're correct about the loud noise of the SRAM drive system there.
It's nice to leverage an existing bike, especially if it's tricked out, so I feel you with wanting to do your own thing. I really don't have a lot of experience with kits but have used
the Hill Topper and will be testing a couple more like this in the coming months. Most are front wheel drive but if you're willing to spend more
the Falco system or any of the
BionX systems are good (both offer regenerative braking, smooth direct drive motors, easy to use control panels and offer mid-mount).
I'm sure you're already aware of those and really just looking for specific advice, wish I could be of more help but have not owned a Townie. I bet there's some good stuff on Endless Sphere. I actually found a couple of threads:
Interesting history here, I believe Don DiCostanzo (Co-founder of Pedego) started out using Electra bikes as the platform for their first electric bike conversions. They were very popular but I think eventually Electra actually asked them to stop using their bikes. Fast forward seven years (I think all of that went down around 2006/2007) and now Pedego is a major ebike brand and Electra has just introduced their own model (the Townie Go! debuted in late 2012 at Interbike). Here's a quick interview I did with their CEO Skip Hess.
Electra has also patented the "Flat Foot" design that moves the bottom bracket more forward for a comfortable, feet forward, seating position. Up until 2013 Pedego was using this design with their Cruiser bikes but ultimately had to change (and did so) in 2014. You can see the frame differences going from
2013 Cruiser to the
2014 Cruiser in the images below ('13 on left and '14 on right with the white tires).