[quote]Is there any way of proving that my ex is bartering his services in order to hide income?

Has anyone succeeded at doing this in court? [/quote]

Well, if you can get one of the parties that he is bartering with to testify against him, you would be able to make a case.

Other than that, there is nothing that you can do. Unless you can prove that he is living beyond his income and doesn't have a corresponding credit card debt. And even then, that's questionable.