HTML_QuickForm_SubForm is an HTML_QuickForm element I wrote to allow making one form an element in another form, effectively making it a sub-form. All elements are put into the form with their original names and all rules put on the sub-form will be called when the main form is validated. In other words, create your sub-form as normal, embed it into the main form, and use your main form as usual.

You can see an example here.

Syntax highlighted code is here.

A plaintext version is here.

I may look into adding a prefix / postfix feature like FormBuilder’s but the problem is that getting and altering QF’s elements is a little hairy.