Let's say that:
You have created a FOSS project that other people find useful, perhaps useful enough to donate to or pay for modifications to be done.
It is a perfectly legitimate and innocuous software project. It has nothing to do with cryptography as munitions, p2p music, or anything likely to lead to a search warrant or being sued.
You want your involvement to stay anonymous or pseudonymous.
You would like to receive some money for your efforts, if people are willing.
Is that possible, and if so, how could it be done?
When I talk about anonymity, I realize that it is necessary to define the extent. I am not talking about Wikileaks style 20 layers of proxies worth of anonymity. I would expect a 3 letter agency to be able to identify the person easily. What is wanted is shielding from commercial competitors or random people, who would not be expected to be able to get the financial intermediary to divulge your details just by asking for them.
Why would you want to stay anonymous? I can think of several valid reasons, maybe you operate a stealth mode startup and don't want to give your competitors clues as to the technology you are using. Maybe it is a project that has nothing to do with your daily job, is not developed there, but the company you work for has an unfair (and possibly unenforceable) policy stating that any coding you do is owned by them. Maybe you just value your privacy.
For what it's worth, you intend to pay the relevant taxes in your country on any donations.