Custom and Custom Made vehicles will do a lot of problems with the ID and, probably, they will go to the "Unidentified" cars that, actually, is a great problem of 3104 cars (only cars: 97 pages X 32 cars).
I doubt these type of vehicles are worth to be listed and to have an own page due the original "maker" is vague (motor from x, chassis from y, etc...)
Anyhow, i'm not going to be the 1st. who say no to these.
If it were in my hand, except custom made and others customs from movies and tv series will be out of the site.

http://www.imcdb.org/movie_396968-American-Hot-Rod.html