David, I got your idea now.
Possible. A lot depends on where this form will be added ( to events, or groups or just on a separate page), but general instructions on how you can create the form itself can be found within "Skeleton" plugin. Download it, visit youristename.com/skeleton page and you will see "Forms" item there.
You will also find some other "tutorials" within "Skeleton" on how to develop things in Oxwall.
Some other ideas:
1. You might want to create a plugin similar to "Contact Us", and just rename/add fields.
http://docs.oxwall.org/dev:crash-course
2 Have you considered integrating free open source survey/questionnaire scripts?
http://www.limesurvey.org - this one looks promising.