Need to know who is building and selling the motor controllers as described in the wiki. I can't build my EV from off-the-shelf components if the components are not on the shelf.
Curtis makes an ac speed controller, most ac motors seem to be sold with matching speed controllers, but I haven't heard of anyone building one from scratch and selling it as a home built or kit built yet so you might have to go with something that costs a little more but has a warranty and a proven track record.