Persistent Autoincrementing Value, Not Attached To Row Insertion?

I need to get a unique value to use for a record *before* the record is added to a table. It doesn't have to be contiguous with existing records, but it must always be unique, has to be persistent over multiple instantiations of an ASP.NET application, and has to work in that sort of a multi-session environment (where other sessions could need additional unique values before the first session gets around to actually adding a record to the table).





I considered generating and using unique CLSIDs for this, but the resulting value also needs to become part of the filename of some files that are being saved to the disk (and those names also saved in the table), and including text CLSIDs along with other filename data would make for some unpleasantly long and difficult to work with filenames.





I also don't think there's a practical way for me to use a trigger associated with an identity column for this, because I need to save files to disk using the unique value before I even know if the record will in fact end up being added to the table, and what's more, the numbers and names of those files will vary in ways that might be difficult to handle in a stored procedure.





What I'm thinking I will have to do is create a separate database table called something like "UniqueIDGen". This table would have a single record in it with a single integer value, initialized to a value of 1. Then, each time an ID is needed, this one record would be locked, read and incremented by 1. The only reason for doing it this way instead of with an application variable, as I see it, is that the values need to be unique and continue incrementing in perpetuity, no matter how many times the ASP.NET application is recycled or the server is rebooted.





But I still have to wonder if there might be a more efficient method provided by SQL Server for this type of unique value generation ... something that is equally as persistent without requiring an entire table with only a single record to be allocated to such a basic task. Does anyone know of a more elegant solution for this?