This article might help you:
http://duncan99.wordpress.com/2009/01/15/cfmail-whitespace-trick/
In short this might strip out that leading whitespace for you:
<cfmail
to = "#Attributes.To#"
from = "#Attributes.From#"
cc = "#Attributes.CC#"
bcc = "#Attributes.BCC#"
replyTo = "#Attributes.Reply_To#"
subject = "#Attributes.Subject#"
type = "text"
charset="us-ascii">
<cfif "#Attributes.EmailUnsubscribeLink#" NEQ "">
<cfmailparam name="List-Unsubscribe" value ="<#Attributes.EmailUnsubscribeLink#>">
</cfif>
<cfmailparam name="X-Receiver" value="#xReceivers#">
<cfmailparam name="MIME-Version" value="1.0">
<cfmailparam name="Content-Transfer-Encoding" value="7bit">
#Chr(0)##EmailBody##Chr(13)#
</cfmail>