Yes, Portrait!Dumbledore has been mentioned to me as well. And I'm not really sure how I feel about the possibility of Dumbledore resurrected, either -- then again, regardless of my current feelings toward the Jossverse, I am from the Whedon school of things and always expect/crave the worst.

Re: Gandalf comparisons, I dislike comparing the series to Lord of the Rings, though I realize that it's impossible to do any serious analysis without bringing Tolkien into it. Which is why I generally avoid HP analysis.

I'm not sure if you've seen the awesome theory of Ron-as-Dumbledore?