The general consensus seems to be that Google isn't checking Whois data.
So if that is true, if two sites are hosted on different servers (IPs), the Google doesn't know if the same person owns the two websites, and therefore the link will be just as valuable as any other from some other...
Dave, I tested it. My site has an SSL certificate that works properly, and on one of my pages I intentionally added an Intertops banner, which is served from a http connection. And voila - the green padlock is gone on all browsers:
(I can't post links yet - visit gamblersfever.net and click on...
I see https in the bar for that above page as well, but there's no Secure green padlock.
Probably caused by some external content which is http, otherwise https seems to be working just fine.