The assumption that Lingayat Brahmin vote will win majority for the BJP is a mere fallacy. (The Brahmin vote is miniscule in the state).
The JD(S) has already largely perceived to have collapsed and all other communities may graviate towards the Congress since the JD(S) is increasingly seen as a loser. This second scenaraio is already visibly evident. It must be noted that Vokaligas and Muslims tend to switch from JD(S) and Congress and back again very freqently.
Vicky's analysis of why SM Krishna is not standing or why Congress is not announcing its CM candidate is based on the later scenario - Congress is trying to be a magnet for all castes and does not want to upset caste equations - very shrewd strategy.
So what evidence is available of a Lingayat-non-Lingayat caste polarization has taken place. The BJP boasted that they had a 15 day campaign lead over the Congress. Now that they hit the campaign trail, they have realized that the masses have very little enthusiasm for them.