I agree with widescreen. Why reinvent the wheel? The time and cost you put into pep armor would be a heck of a lot more than if you start from scratch, plus you'll have something that you can wear or display in weeks, rather than months...or years...or never (due to frustration). Of course there is a certain satisfaction you get from building it yourself...
I've built a pepped one, and it only cost about twice what a bought one would have... Plus it only took about three years... But it was a lot of fun. I've got pep files, but I'd honestly recommend you get a set from somewhere like Anovos.