1968 Volkswagen Beetle

I was thinking about converting my bug to an EV but am a bit skeptical about the range/speed the pure electric power would allow. I’ve been doing some research and it seems that most conversions only get about 40 mpc at a top speed of 60 mph (and those are under ideal conditions). I was wondering if anyone has any experience outperforming this.

Note: These cars were using the lithium-ion batteries. Also curious as to whether or not the new Nanotech A123 batteries might allow for better performance.