Paypal doesn't have to know everything. Many people use it to get payment for their adult transactions. They make sure to tell their customers to leave the "Subject" field blank, or if they feel compelled to use it, to type in WiFi, or something safe. Your site fall under the "Service" category in terms of payment type. So donators can use that category, and leave everything else blank.
As long as no one blows it, the account remains in good standing.
Take it from someone who was shut down once, and is now under review because a custom video customer decided to post his custom name and script in the "Subject" and "Comments" fields.
When PP shuts you down, simply use a different bank account, as Paypal makes sure the one in question never gets used again.
Also, I propose two things, shop for better hosting, and increase the number of donators. Go to
www.cozyfrog.com and GFY (just type it in the Yahoo or Google search box, and you will see what GFY means). There are lots of adult webmasters with excellent hosting plans for you. Tell them what you are paying, and most will try to beat it so they can get your business.
As someone said eariler, $60+ is a car payment for some people. Try getting 20 or more dedicated donators. You can even set Paypal up to automatically bill their accounts each month--just be discreet. $12+ is a lot easier on the pockets. I suggest the donators should all be moderators, as they will truly be the driving force of the site.