Hi Sarah,
yes, I used to do it and it's quite easy. Just copy and paste the HTML code of the 1st email to the 2nd one; then add some paragraphs above the first line of the "forwarded" email. Apply simple formatting to these paragraphs so they look like they were written by a person (like Arial, 12px, or Calibri, 11px). 
Example:
	<p style="font-size:11pt; font-family:Arial, Verdana, sans-serif';">Have you seen this email below?</p>
Don't forget to add fake sending details above the 1st letter:
From: 
(label that the 1st email was sent from)Sent: 
(approximate time and date of sending)To: {{Lead.First Name:default=}} {{lead.Last Name:default=}} 
(tokens are really useful here)Subject: 
(1st email subject)
	 
You can also add a line between your 1st letter and "personal" text, just like in emails that are really forwarded. I add this line by HTML tag <hr /> (horizontal rule) between paragraphs.