Originally Posted by Jonesandrew

Front hub motors cannot be used because the front hub is I believe, unique in the cycling world. Even though it's apparently made by Formula who I understand make the Lefty hubs for Cannondale, it's done in a totally different way to allow the shaft for the wheel to wheel locking mechanism to pass through the centre. While we're on this subject, centre drive motor systems also will not fit Helix because both wheels are tight up to the bottom bracket when folded.

@Bym: It looks like titanium spokes could be used to reduce weight but after a very quick investigation, the perceived wisdom on the net seems to be that by the time you've got the spoke thick enough to equal the stiffness of the steel spokes you are replacing, you've lost the weight advantage. If you don't mind loosing stiffness you could save a few grams.