Is there a way to force sp_send_dbmail to use ANSI, or to not include the Unicode prefix?
I think you can generate the reports using powershell and then use DBMail to mail the attachments

Write-host "Running SQL Query to export to ANSI CSV file"
Invoke-Sqlcmd -Query $dbQuery -ServerInstance $instanceName | export-csv $targetFileAnsi
Write-host "Running SQL Query to export to Unicode CSV file"
Invoke-Sqlcmd -Query $dbQuery -ServerInstance $instanceName | export-csv $targetFileUnicode -encoding "unicode"


$dbMailQuery1 = "execute msdb..sp_send_dbmail 
@profile_name = 'msft_profile', 
@recipients = 'seths@microsoft.com', 
@subject = 'Email with Attachment - ANSI attachment', 
@body_format = 'TEXT', 
@body = 'This email has ANSI file attached to it', 
@file_attachments = 'c:\temp\result_ansi.csv' "


Source: http://blogs.msdn.com/b/sqlagent/archive/2011/07/06/email-query-output-as-ansi-unicode-file-attachment-using-powershell-and-database-mail.aspx