Red Evolution have devised a fantastic new keyword tool which lets you create your own scenario for a search query. After creating the scenario, a unique URL is created which you can then email to friends, post on forums,  send to people to test for you, etc. These people then enter the search phrase they would use for each scenario and the system generates a seed keywords list.

An example scenario can be found here, I’m looking for somewhere where I can advertise my services and products. and you can use the same page to create your own scenarios.