While ugly, I'm certain the following will work:
<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">#Trim(EmailBody)#</cfmail>
I've had problems in the past where the cfif tag leaves whitespace behind when the conditional logic evaluates as false. Placing the entire tag through the close tag seems to correct it.
Also notice that I wrapped EmailBody with a Trim().