Take a look for female super hero costumes - catwoman, wonder woman and so on. Once you've got a shape to work from you can just apply liquid latex to it for the skin. I'm assuming you want to make it to show off the female form, if not then just use a mr I suite and take out a little of the muscle to make it less masculine
If you want a female muscle suit, than I'm afraid you are out of luck, I've never seen one. If it doesn't matter, then do what scanff suggested and get a catsuit that you can latex over.
Take a look for female super hero costumes - catwoman, wonder woman and so on. Once you've got a shape to work from you can just apply liquid latex to it for the skin. I'm assuming you want to make it to show off the female form, if not then just use a mr I suite and take out a little of the muscle to make it less masculine