Hi, Jeff,
Yes, Enterprise forms is licensed on a per-domain basis. But you may be able to discuss unique licensing needs with them - dunno.
You can indeed test out their modules online, but that doesn't really allow you to test drive the more powerful aspects. For example, one of the features I requested some time back was the ability to run an SQL statement at work flow steps. So - Enterprise forms will store the data in its own generated tables, but I am able to at the same time take any of that data and via a stored procedure, do absolutely anything else I want to do. This means that I can (and have) create a suite of forms which are not connected in terms of how Enterprise forms looks at things - but with my behinds the scenes programming I can link them together by joining on the EF tables in a stored proc, and then populating views or tables after manipulating as desired.
With the latest version, you can databind elements to data from Oracle, mySQL, Access, VistaDB (maybe more) as well as from the DNN or other SQL database.
There's a lot of functional power here but as you note, I'm not sure how this might fit with your particular project.