Interesting discussion, but there are simply too many variables to determine the precise effect of your linking question.
Everyday I see links from sites with MUCH LOWER "pagerank" getting listed well above sites with high
PR values. I think the old ideas about sharing juice with links may have to be re-thought due to Google's recent and dramatic adjustments to its ranking algorithm(s).
It appears the OLDER SITES do seem to still have more "value" than younger sites do, no matter what else we are considering.
After all, the AGE of a site is the most difficult parameter for a potential spammer to game.
As the web becomes more and more filled with - frankly - crap, I'm sure that Google will rely more and more on the age of a site in its formulas about the final worth of a keyword ranked search position.