First off Ceige welcome to the forums!
Regarding the first question I have seen a clever space ship built out of a old computer mouse. Another modeler made a 1946+ German rail canon out of one as well.
Far as the 20 000 Leagues submarine check out Moebius models, I believe they released that in plastic.
http://moebiusmodels.com/
Ok I may be wrong there. A recent article in FSM had the submarine featured in a detailing article, thinking it was a resin kit though...