i started a new site only 4 days back on medecine .. 2 days back i made at least 10 subdomains of this site on various subjects .. , i submitted all the subdomains to some directories ( related directories to the subdomains content) etc in order to get backlinks ... Today when i checked the Future Page rank of the main site , it has increased by 4 !! ... Subdomains have great importance ... Subdomains also has a probability of only 1 % of getting into the Sandbox ... Rely on Subdomains guys.
Sorry, I do not see how you are putting this all together. This is about as useful as me saying it is raining today because I have brown socks on.
hmm ... if the subdomains have got each a PR of 2 , and they are linked to the main domain .. in this way the main one will surely get a higher PR.