You are not going to be able to find anyone renting a PC jacket with a 5-button vest as the two just don't go together. With the cut of the PC jacket, a 5 button vest really would not look right. You need the low-cut button PC vest that was designed for the jacket.

Why not get a black Argyle with a 5 button vest?

I know there are a couple of places in the US that rent an Argyle cut jacket. The Scottish Tartans Museum only has PCs to rent, but I believe Scotland Yard rents the Argyles. The problem is that I don't think they rent the 5-button Argyle vest. You may have to end up purchasing the vest and renting the jacket.

The problem with that scenario is that you run the risk of the two fabrics not being a match, and you never know how good that might look. On the other hand I bought a 5-button black vest in cotton from a completely different manufacturer and some 6 years after I bought my black wool Argyle jacket -- completely different materials, but the shades of black are spot on and the two look splendid together! So you never know!
Matt