N637US was,
Airfleets claims, stored at
Pinal Airpark outside Marana, AZ in June of last year. This would jive with Airliners.net having no photos of it after last April. Of course, it's in the new paint, so it's not one of the many red planes visible on Google Maps.
So... that'd seem to leave us with N623US, N624US, and N638US... but this is really a big guessing game. I think I know someone who might know someone who
would know... I'll try asking.
