Actually you have quite a selection to chose from for building yourself a Rat Rod.
I'm not trying to advertise my site, as it is not ready for prime time yet, but it is easier to list items just by pointing you their (hopefully I won't be in trouble with any policies or moderators). Take a look at options you have here - 1920 - 1940 cars and trucks. There's actually more as I haven't updated the info for awhile.
GoodGuys sponsors some nice car shows, some of which include Rat Rods as seen here - http://www.ratrodderalley.com/node/14
Don't forget about customize the kits too.