It's actually an extension to an add-on created for AVForums by @ExtraLicense.
I have since added some additional options:
It allows you to create subjects in the form of "Recipient Groups". A recipient group is selectable from a drop down list on the contact form:
Contacts to a recipient group can go via email, or posted in a specific forum or both. For some recipient groups you can also specify one additional custom field, e.g. that was done to prompt people enquiring about advertising for a telephone number.
Seems like it could do what you want. I'm not sure of release date, yet, though.