How to render a VisualForce email template to string

Question

Is there a way, using Apex, to trigger the rendering of a VisualForce email template and capture the result as a string?

This would be used to set the HTML Body of an email to be sent using an external service (HTTP call-out)

Answer 1

Yes -- this can be done with a clever solution from this SFSE wizard @PJC

https://salesforce.stackexchange.com/a/8745/2602

Leverages the apex SavePoint and Rollback to trick SFDC into rendering and retrieving the rendered value