Rebel Mike has started a great thing, by creating an online bits box for all your modular vehicle and conversion needs.
It's called the RUMV store.
A beautiful bunch of bits, eh? More to be added as the RUMV system is printed and cast. Here's the link...
New RUMV Store, Hulls, Engines, Weapons, And More
Also, due to the modular nature of my work, you may also be interested in these parts...
HAMR Suit and VTOL Bits
Comanche Gun Cupola And Weapons Set for $2.99 (Possibly the best deal going in the world of 15mm)
Next Up: Rebel Gun Drones.