Okay, at least you can “hide” or remove the sidebar with some CSS:
/*Hide sidebar*/
#sidebar { display:none !important; }
/*Full-width posts and pages*/
#custom, #container, #post-entry {width:100% !important;}
/*Full-width BP components*/
#custom #container #content {width:100% !important;}
#custom #container .padder, #custom .directory #container .padder {width: 96% !important; padding:0 2%;}
Source: http://premium.wpmudev.org/forums/topic/buddy-press-sidebar-on-some-pages
Regards