The mobile Bat Lab by Mego is one of those "I missed a meeting as a kid moments" as I have virtually no memory of this item. As far as I know, I never saw it in a store, nor on television, despite friends telling me they had it growing up and it definitely was sold in Canada.
When I first saw this, it was through the eyes of a cynical pr- teen, who immediately thought it esoteric and goofy. While the image of Batman rolling around in a VW Bus, getting high and catching criminals like some sort of vigilante Jeff Spicoli is infectious, I bet I would have loved this as a kid.
Of course, I own one now....
The Mobile Bat Lab made into this list The Top Ten Coolest 70s Batman Toys.