Digging through the details leads to following as available Admin Imposeable restrictions:
Attachment Settings:
The maximum number of private message attachments that will be stored on the server. Use a value of 0 to allow unlimited attachments.
Private Message Settings: If enabled, users may attach files to private messages.
So nothing really which lets Admin impose a direct limit on "Number Of Messages" ...unless i am missing something pretty obvious
HyTC
Attachment Settings:
The maximum number of private message attachments that will be stored on the server. Use a value of 0 to allow unlimited attachments.
Private Message Settings: If enabled, users may attach files to private messages.
So nothing really which lets Admin impose a direct limit on "Number Of Messages" ...unless i am missing something pretty obvious
HyTC