UPDATE

It looks like I am re-designing this one from the ground up more than just tweaking EM. There is good reason for this, as there seems to be a few advantages. Also, I think User Monitor is going to be a little different to Editor Montior (as it should).

So far, your Users table is going to be extended by quite a few coloums (I hope this does not have any major problem on performance, but I suspect noone has 50,000 users, so I don't think you will notice anything).

UM_Bio - TEXT - Bio on user
UM_Address - CHAR 150 - Users address
UM_Status - CHAR 75 - Definable user status like in EM
UM_UserSince - Date when user was validated
UM_TotalLogins - INT
UM_LLA - last login date/time
UM_LLB - 2nd last login date/time
UM_LLC - 3rd last login date/time
UM_Notes - TEXT - custom notes
UM_Rewards - INT - same as for EM
UM_LastPaid - same as for EM
UM_AmountPaid - same as for EM
UM_CustomA - TEXT - whatever you want
UM_UserRating - INT - user feedback rating column for inclusion in future version
UM_SettingA - CHAR - this is for UM use only
UM_SettingB - CHAR - this is for UM use only

The users table already contains Email. Other information, such as the reviews a user has written, and links owned by a user, will be calculated by UM.

How much of this will be soaked up by future updates of Links, or an addon like G-Community is anyones guess... I just hope this is not all for nothing in any case. I'll plod in with it in the mean time, and hope to have version 1.0.0 ready soon. Same price as EM.