Well here *IS* a way to set your start posistion. I found the util on here in the util section. but you have to create the scenario, then run it and save it before you do ANYTHNG!
Then you run this util and it will re-save the scenario with your pre-set starting positions.
The only drawbacks are:
1.) You have to load a saved game, not a scenario
2.) You need to use the civ editor and figure out the EXACT starting positions for ALL the civs in your game and then change the example that comes with it to your locations.
But it does work... I created a nice map and then put myself on a continent all by myself!!!
Let me know if you can't find the util I am speaking of, I will post its link here if you need it!