Digital Sewing Patterns?

Hello! I have an idea for a Halloween costume that involves using a service like Spoonflower to create custom fabric to make into a suit. However the design isn't just an all-over design that I can just lay the sewing pattern over and cut out, but instead relies on me being able to make a custom design specifically for each piece of the suit pattern. Basically, I want to do something along these lines, only for something larger like a man's suit.

I'm trying to find a digital sewing pattern or template that I could open in Photoshop so I could design each piece of the pattern the way I want it, but either I'm really bad at searching for stuff on the internet, or this sorta stuff is super rare/doesn't exist. I could buy a pattern for the sort of suit I'm looking for, but I'm not sure how I would be able to scan or otherwise transfer that pattern into the computer in an accurate way. I'm afraid I will scan the pieces in poorly and end up with an unusable pattern by the time I'm done.

So I suppose my question is: Does anybody know if there are any patterns available in a digital format somewhere online either for free or for purchase? And failing that, does anybody know a reliable way of digitizing a pattern that will insure that the measurements won't be screwed up in the process?

Thanks!