I've used the rods to join the 2 halves of the frame together rather than cutting mdf, it's strong and light and once you get the hang of aligning holes much easier: I just slot the bits together.
I've used it to make control levers also (with white beads for knobs)
Also I think the extra type of material adds to the overall finish.
I realised the other night that my bike needs a really cool exhaust, after rummaging through my bits box I found these sweeping curved tubes, which once sprayed looked just right. I had a bit of trouble securing them but finally slotted thick wire inside and then sank them into dowel, this was then fitted into a plastic drum. Fortunately I had drilled decorative holes into the frame (see top photo) so 2 more bits of dowel allow the whole thing to slot onto the frame securely enough to take the weight of the long exhaust.