What about using the same format as a standard Guid.... Create a 12 Byte
array, and just increment the values in them (Assuming you will have a single
central place where you create these "Guids" and then converting the result
to Hex since each byte would have a numeric value of something between 0 and
255.
Another option would be to take the machine name and the date and time down
to the millisecond and combining that into a 12 byte array before doing the
hex conversion. (Just make sure that you application can then not create more
than one "Guid" per millisecond. Combining that with a random number may sort
you out, but you will still not be able to guarantee uniqueness, but you’ll
probably be close enough. All depends how deep you want to go.
Someone mentioned something about looking at the security namespace and (I'm
guessing) look at some hashing... but then, what are you going to hash.
Anyway, hope my ramblings help at least a little bit.
David