The following video demonstrates a PHP script that you could run on your own website to collect body measurements from prospective customers. After filling in their contact info and their body measurements this information could be e-mailed to you with an attached BCAD file. The BCAD file has the customer's contact info pre-entered in the Notes tab and the customer's body geometry pre-entered in the Fit advisor.
A functional example of the form is shown below. This form is in inches, but the zip file below contains both a form in inches and a form in metric.
To test the script on this page, fill in your own e-mail address below along with your own contact info and body dimensions. The resulting e-mail will be sent to your own e-mail address. (The actual script would e-mail the customer's info to you, not to the customer.)
If you would like to install this script on your own site, you can download it for free from here.
If you would like to offer your customers the option to design their own bikes online, checkout BikeCAD for the Web.