Great plugin - I would like the ability to add a registration field that can draw upon a Custom Taxonomy.
The site I'm developing has dozens of authors who are affiliated with 1 of 7 different broadcast stations. Using the Custom Taxonomy capability of WP 3, I have a set up a 'Stations' taxonomy - e.g.
KQED - San Francisco, CA
WXYZ - Boise, ID
KSTN - Madison, WI
upon which I can perform various operations based on Station affiliation. In Register Plus Redux, I can currently create a Select field that lists the names of the stations, and make a pull-down menu the user can choose, but I'm just replicating terms that exist in my Custom Taxonomy. It would be super useful to be able to select/access a Custom Taxonomy to create the additional fields, instead of creating new Custom Fields.
If there is already a way to do this, please let me know. But I did not immediately see how it could be done.