You don't need a pro account for Express only. It is completely free.
I followed your link that says that paypal standard doesn't require a paypal account... but nowhere does it say that express checkout does. Your customers are not forced to set up a paypal account...
I have attached a screen shot of the form your customers will see at checkout with express checkout...
It clearly has an option to checkout without a paypal account and it clearly states that creating an account is optional at the bottom and lets you decide whether you want to or not.
This is no different than Paypal Standard.
I also found this link on yahoo that talks about it and shows screen shots that contradict your assertion that a paypal account is necessary or even created automatically.
paypal-41.html
