Dear Sudhaama Sir
I have not read "Sankara Vijayam".What I had read was Shiva appeared in his parents dream and gave them a choice.Whether they would like 100 sons or a bright son who will live for a short time.The couple chose a bright son.I do not think that Shiva said he himself would be born as a son for them.In honour of Lord SHiva who granted them a boon, he was named "Shankara"
Shankara has also composed lot of slokas on Lord Shiva.Shiva will not compose slokas on himself! Also, soundaryalahari is supposed to have been certified by Lord SHiva in Kailash itself.
Shiva appeared once before shankara with four dogs representing Vedas and corrected him.Adi shankara got sick and composed "subramanya bhujangam" in praise of Murugan at tiruchendur(or thiruthani).Lord Murugan cured him of it.Hence, from these incidents i think, Shankara was a human being who was an "extension" of Lord Shiva and one who was blessed by the Lord.I do not think Shankara was the Lord himself.
This is just my belief. If you think otherwise, I'm sorry if I had hurt you.
Anyway,let us continue discussion on Ramanujar on this thread.