From: geni geniice@gmail.com
172 and Guanaco have both lost their adminship due to arbcom cases. a full ist of admins who have lost thier adminship (for a number of reasons) may be found at [[Wikipedia:List_of_administrators#Former_Administrators]]
In addition, as I said before, other admins have had admin powers temporarily revoked, or have had other sanctions placed on them.
Jay.