Not to mention any legal issues if you tow over limit and are either discovered or in an accident...

You may want to look into a heavier duty vehicle if you tow often, or there are commercial rental agencies.

I've looked at renting a F-350 for a weekend from Enterprise. They call it 'commercial' but that's just them, you don't have to be a business. It's not cheap, but it's cheaper than buying your own! Doing some quick math a while back, I think we figured we could rent 20 days / summer (tow a boat) for way less than buying one. Especially when you consider insurance, fuel, maintenance, etc.