Id like to chime in on this question simply because i run a few SSL sites one used to be non-SSL and i turned it full SSL
But take paypal for instance.
https://www.Paypal.com has PR8
http://www paypal.com redirects to the https version.
If google treated pagerank exactly the same on SSLvsNON i'd argue that a page such as:
https://www.paypal.com/uk/webapps/mpp/paypal-fees (paypals fee's page) would show some PR and would not be given PR0 by google, its physically impossible.
So what i've always believed is that google will run site wide PR when using HTTPS.
On the site i used that was nonSSL and is now SSL, the non SSL pages was individually ranked, since switching to SSL only, those pages do remain individually ranked on one google PR checker.
But on the other, it shows the site wide PR.