Ceiling Fans, Fans & Ceiling Fans With Lights | Rejuvenation
I have never purchased anything from Big Ass Fans, so I have no idea how customizable their stuff is (though I'd imagine it would be, given that they're $$$).
Another option is a store called Rejuvenation. I was in their store today and have purchased lighting fixtures (though no ceiling fans) from them in the past. Very customizable. They have a line of ceiling fans, now. Customizable rod lengths. They are based in Portland, OR, but have some brick and mortar stores, too. And for Herr Oberst's suggestion for poking hundreds of holes in the wheel barrel and lighting from the interior, you can check out some of the mid-century modern lighting fixtures from Rejuvenation for a similar idea they do (though on a smaller scale than a race wheel).
edit: OK, I've sent you on a bit of a wild goose chase. Looking at Rejuvenation's website, they don't have a dedicated category for all their mid-century lighting. So type in "Galaxy" or "Corona" into their search feature for the lamp shades I'm thinking of.