Would this be considered black hat?

No, there is nothing black hat in this... I have seen many automobile website creating different home page for different models and this approach is working working fine for them.

But make sure there would not be any canonicalization issues.

Don't forget to use canonical tag to those sites

Well your already in the whore house so slip on the knee pads like a good little HO Because if you don't there a are plenty of real sluts out there who will be more than happy to take your client and your money and give them a grin as they wipe off there chin with a fist full of your money. LOL

It is not black hat.
But if you create sub domains that may help you better.

Subdomains is cetainly a bad idea - I had subdomains on one of the promoted site and recently it dropped greatly - after deleting all regional subdoamins it went back, so i think it's bad for Google, else you have totally unique content on each, though I wouldn't risk even then. As for separate websites I don't think you have to block bots on them, just take care to have unique content