Have you heard of LiveCycle Designer? I haven’t until just recently, I didn’t even know it was an Adobe product until I discovered a tutorial series at Flexlive about building forms with LiveCycle Designer to use in Flex. The first part of the multi-part tutorial is posted, and I have to say, this sounds very promising for Flex enterprice application development.
Basically you define an XML Schema with your favorite XML software, bring it into LiveCycle, and then create and test forms directly within the LiveCylce application. I awaiting the rest of the tutorials so I can understand the magic of transitioning these forms to Flex. I highly recommend reviewing the video tutorials.
I am not sure of the LiveCylce pricing, but I do know they just released an update that allows you to use it without the associated server. You have to contact an Adobe sales representative to actually get a price. However, you can get a trial version by filling out this form.