I am specifically thinking about unsigned int.
Here is a practical example: what do you do when your identity column maxes out? It's possible to either go BigInt (8 bytes storage instead of 4) or to refactor the application to support negative integers, and even to create your own rules as indicated in this answer; neither of those options are optimal.
UInt would be an ideal solution, but SQL Server does not offer it (where MySQL does).
I understand that unsigned datatypes are not part of the SQL standard (SQL-2003) but still seems like a waste to me.
What is the reason of not including these (in SQL Server or in the standard)?