The large sized PRST 4 frame is relatively rare, much more common are medium frames.
They are 20mm shorter than the Large frames from seat tube to headtube which is not a difference that was very obvious when riding them. I'm 6'3", and had no problems at all riding my medium framed PRST's, so it might be worth expanding your search in that direction.
When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.