For those of you who use PRO and are trying to do something similar I threw this together for a project I’m working on. We didn’t need the dropdown forms but we liked the rest so we added a little ajax of our own.
http://pastebin.com/86KWkCCv
NOTE: We use Google CDN for jQuery so the $ notation wont work with default WP just change to what you prefer.
When the change happens the first time it shows the default arrow for a split second then never does it again. Pretty odd. We’re actually changing it to use arrow graphics and using .data() instead of .html