People always say things like this but unless you itemize this is not useful. I am assuming, based on the OP being willing to tow a 1k+lb trailer with a miata to save a few bucks, that he doesn't make a lot of money or have a complicated tax situation so he likely uses the standard deduction. Just my thoughts on the whole tax deductible angle.

I would still dish out the cash for a truck because its a lot less costly than hospital bills, lawsuits, or tickets. Not to mention the whole safety factor.