Sure. The form is only html. Actually, Nvu does have extensive support for form creation and editing. Check out the icon immediatly to the left of the "Spell" icon. You could also Cut N Paste your form code from FP and inset it into another editor, or just modify the form code using the html view of FP to modify the "action" part to use another form processor than the FP extensions.
In other words, creating the forms is most lilkely not your real problem, as the missing FP extensions are more likely involved in processing the form, which you will still have to do.
Dreamhost provides the use of a fairly robust form processor with your account, and it is pretty easy to modify your form to use this if you invest a little time in learning how to configure your form. Information for doing this is located at http://formmail.dreamhost.com/