I’m pretty sure this is allowed, but think it depends from one brand to the next. I know that now in theory you are not allowed to own a domain name with the word “drupal” in it.
What If I build a fansite with the (hypothetical) domain name ford-grand-torino-info.com ? Is there any way of verifying if I’ll get in trouble for this?
I would be surprised if there’s any law against it, but I’m interested to know what others have to say.
Is there any way of verifying if I’ll get in trouble for this?
About the easiest way to get into trouble is asking for legal advice …from people who aren’t lawyers …in a forum about writing. SitePoint has a Business and Legal Issues forum.
The issue is trademark infringement. Merely using a trademark is not necessarily an illegal infringement, but it can be. It depends on what you do with it.
I wouldn’t even bother registering a domain which is the same as a trademark (even if it couldn’t be mistaken based on what it sells). There’s just too much of a risk that someone may find some obscure reference that they confuse for the words or position of the trademark owner and you could end up facing some difficult decisions in reference to whether your brand can continue to practice like that. Arguably your site could qualify as a violation of the anti cybersquatting legislation too (if you just hold the domain and don’t use it). It’s much safer to have an original domain name with no confusion attached. 
Other than what some folks mentioned about trademark, do a Google/Yahoo/Bing
search for any domain-trademark dispute involving the one in question.
I think its better to think of nice set of keywords for your url than using a brand name as part of your domain.