Consider me interested. What are these cheap knock-offs of which you speak?
Usually special eggs dedicated to a single children's cartoon (Hamtaro, Hello Kitty, Kabouter Plop) containing a figure from that show. I believe these are not from Kinder (and the insides were a semi-clear colourless plastic). Also, I believe stores like Aldi and Lidl also have their own home brand versions of the thing which possibly has the old style inside too.
As said the plastic is horrible and the vehicles shown in the first post owe much more to good scratchbuilding skills than to the shape of a Kinder egg