Here's an old recipe from someone named Randy. I have tried it, it's good.

1 qt. water
2 1/2 cups Splenda
3 TBS instant coffee
1 TBS Vanilla
2 1/2 cups vodka ( I use good vodka when I make this)

Bring water, splenda and coffee to boil in sauce pan. Simmer very slowly for
2- 2-1/2 hours, or until mixture is very dark and syrupy. Cool completely.
Add vanilla and vodka. Makes 7 cups.