I'm based in NYC and have needed US date formats for my customers. It's not comprehensive, but for adjusting the CMS I've used the following successfully:
/jsparty/calendar/calendar-setup.js
Change line 5 in initialise()
ifFormat : "%m/%d/%Y", // the date format
Change line 32 in setToToday()
this.value = ( date.getMonth() + 1 ) + '/' + date.getDate() + '/' + date.getYear();
/sapphire/forms/DateField.php
Change line 18 in setValue()
$this->value = preg_replace('/^([\d]{2,4})-([\d]{1,2})-([\d]{1,2})/','\\2/\\3/\\1', $val);
Change line 29 in dataValue()
return "$parts[3]-$parts[1]-$parts[2]";
It would be nice to see the d/m/y (m/d/y) type code moved to the _config.php file so it could be easily updated. Has anyone done that successfully?
Hope that helps someone!
-John