First part of avatar persistence, currently only really works in standalone mode (with accounts_authenticate set to true), it also only currently has a mysql database connector. (sqlite one will follow soon). It also uses the tribalmedia database system, so this needs checking to see if the old problems with mono have been fixed.

To use, see the appearance section in opensim.ini.example, set "persist = true", then add the correct connection string for your database.(see mysql-AvatarAppearance.sql in share folder for a example of the table mysql table structure).
This could possible be used in a very small grid, but would mean each region server would need to connect to the same mysql database. 
But the work to move the code to one of the grid servers shouldn't be too much.

OpenSim/Framework/Data.MySQL/MySQLDatabaseMapper.cs

@@ -1,10 +1,11 @@
 using System.Data.Common;
 using MySql.Data.MySqlClient;
-// using TribalMedia.Framework.Data;
+ //using TribalMedia.Framework.Data;
+
 
-/*
 namespace OpenSim.Framework.Data.MySQL
 {
+    /*
     public class MySQLDatabaseMapper : OpenSimDatabaseConnector
     {
         public MySQLDatabaseMapper(string connectionString)
@@ -22,6 +23,6 @@ namespace OpenSim.Framework.Data.MySQL
         {
             return "?" + fieldName;
         }
-    }
+    }*/
 }
-*/
+