There are a few ready made templates online.
Here is one [url]http://webpages.charter.net/rbecker5/plans.html#design/url]
Although I'll warn you, you don't want the player 3 and 4 sticks angled like they are in this plan.
You want them so up points up.
Also you don't need any more than 4 buttons for player 3 and 4.
If you have an art file set right (say 300 pixel per inch) you should be able to have it printed to scale at a local kinkos or something and use it as a template.
If someone produces a template for you, you'll still have the same problem of getting it printed to scale.
One thing is if you're working with a 300 pixel per inch file and you want something to be an inch when printed, then you wound make it 300 pixels
This procedure has been covered a few times around here so I won't explain it more because I'm just not good at explaining it.
If you want to go two player, I can sell you my original controller top