in the other way (if really need custom form and workflow didn't cover your cases ) you can develop rest-application (or pay to freelancers) to solve your problem: build your own form (not a constructor, just simple form) and place on your own web-site.
Nice!
that's my real need. I have a Deal associated with a company. At 1st I fill the basic info about them, than I want to send a link so they can fill the rest and upload some documents