I am using Fogbugz for my own personal work plus I also work for clients who have their own Fogbugz implementations. I have created custom filters, workflows, categories and statuses that I would like to copy to my clients account.
Unfortunately, it looks as if FogBugz is deficient here. The XML API permits you to retrieve a list of filters (via cmd=listFilters) and a list of Categories (via cmd=listCategories), but there is no way to retrieve the status or workflows, or to set any of them, via the XML API.
You can always do this by retrieving records from the underlying SQL database and setting them up in the new account, but this is a bit of a pain in the neck.