Was the "article that claims maximum 50 users" written by someone attempting to cast doubt on VFP and/or wanting to promote another database environment?
Since way back in the FPW days it was not too unusual for us to have clients with applications working for 100's or 1000's of users. Obviously not ALL of those users would be concurrent users, but I can guarantee that it would typically have been over 50.
I seriously doubt that VFP has downgraded its concurrent user limits since the FPW days.
Good Luck,
JRB-Bldr