Shawn,
Its probably too late to help you, but we're in a similar boat with a multi-vendor deployment and attempting to standardize our logs. I know Cisco gives you the following options for a mac-delimiter on their WLC's:
colon, hyphen, double-hyphen, and no delimiter.
So you could standardize on the Aruba format. I'm still going to make a feature request with Aruba to support this capability.