The Seven gained popularity for the same reason as its most direct descendant, the Lotus Elise, did: it was a lightweight, totally bare bones sportster. Thanks to it's feathery weight, it didn't take much engine to make it go insanely fast, just like an Elise. So it makes sense that just as the Elise has spawned the Tesla Roadster, the Seven should give birth to modern energy efficient variants. There's no word yet on price or availability. Since Westfield doesn't build engines and multiple drive-trains are available for installation in their cars, it would seem likely that they'll adapt an existing hybrid drive-train, likely from Toyota or Honda, to their vehicle layout.
[Source: Westfield SportsCars]