Hopefully, others will have better ideas, but there is no dedicated tool I know of. For mobile acounts dscl may be of some use:
dscl . -read /Users/$USER AuthenticationAuthority | grep LocalCachedUser
It will find nothing for a network user that isn't cached, so looping through local home directories and checking for a local directory record for each might help. If you're looking for non-mobile logins with no local home directory, try the "last" command, keeping an eye out for non-local users.
Also note that if you're using Active Directory, the UIDs, (visible with id -u) are much larger for AD accounts than native OS X accounts. Simply sorting accounts by UID is often enough to figure out which is which.
