Large Identifier Uniqueness Across Table
Perhaps look into Jimmy Nilsson's COMBs? Discussed here: https://stackoverflow.com/questions/1155454/performance-value-of-comb-guids
Or, if you don't need uniqueness over several SQL Server instances, just some int-type with a sequence or identity? (As suggested by Mo64.)
The fact that NEWSEQUENTIALID() is &quot;re-seeded&quot; at re-start isn't anything we can prevent, AFAIK.