Like the terms "cafe racer" and "streetfighter", "cult bike" is some times a bit difficult to define.
I see most cult bikes as enthusiast bikes that were sold in the states for a short time and then discontinued because clueless American riders didnt get it and wouldnt pay for it.
Examples of the type include the Yamaha SR500 and SRX600 singles, the Honda Ascots, GB500s, CB-1 400s and Hawk 650 and the Kawasaki W650.
However, just because a bike is old(er) and still has a following, doesn't make it a cult bike. I would exclude the Blast from the category because cult bikes have one other thing about them that they all must have in order to be a cult bike...they have to be cool.