I enjoyed the Hot Wheels group shot.
Perhaps put powder coated covers over the capacitors? There would be no concern about the temperature needed to powder coat the covers.

Is there a certain place you could recommend for supplies. I think I want either copper color or black.
For copper, How about slipping the caps into a piece of copper tube, and polish to your hearts content!!
Regards,
John
The ends would still be aluminum unless he soldered a flat piece of copper to the end of the tube. Then there'd be the solder showing most likely, plus the cutting and shaping the end where it meets the tube..