Build form like functionality into email

In some ways it's surprising that this hasn't already been done (or perhaps it has and I haven't seen it). Often people ask for structured data via email, with that email going to a number of recipients. There are a variety of ways this is currently done: a simple message to and fro; a message with an attachment to hold the data in a structured fashion; or the use of a web-based tool like SurveyMonkey.

It seems to me that most email programs these days handle HTML (and potentially javascript?) and as such it might be possible to build form functionality into the body of an email. The recipient would not need to go online to fill in a form, or download and open an attachment, but natively respond via email in a structured format.

The process would look something like the following:

• the sender (who requires the data) builds an email with a form generator tool (selecting widgets such as dropdowns and input boxes);
• the sender then sends the email to the recipients
• the recipients open the email, fill out the form and reply
• local javascript input validation would prevent the reply email being sent without required fields being filled in
• the original sender would receive the reply in a structured format
• the email application of the original would collate all responses, tracking those not received and build up a database (single table spreadsheet / RDBMS style / object oriented) of the responses (or potentially the receiving email address application could be set up to pump the received data into a server-hosted database)

The advantages of this system are that there is no need to move outside of the email application to use web forms (can be done offline, then sync), and that structured data is collected into a useful format without manual copy-paste.