Google "PPV Split Test", "PPV Campaign", and "PPV Case Study."

I have found over 10.

PPV Spy from unfoldads.com has a trial discount last time I checked, their database is nut terribly up to date, but they have 800 or so sample landing page screen grabs.

There's a decent report on a myPCbackup campaign out there that a search should turn up.

Any particular criteria for the case study required?

(what are you trying to achieve?)

Website and landing page testing case studies
Dynamic landing page case study | PPC advertising optimization
Studies for dynamic landing pages, and also:
http://www.thesearchagency.com/sites...Protection.pdf

great study in .pdf, go check it. You're welcome