From 2008 onwards you can create a basic profile and then override the details with @from_address/reply_to
;
EXEC msdb.dbo.sp_send_dbmail
@profile_name = 'my profile',
...
@subject = 'The Spice must flow',
@from_address = '"Bob Smith" <xxx@yyy.com>',
@reply_to = 'xxx@yyy.com'