In Narayana Nagar 1st block, back in June 2011, north facing 60 X 40 site was quoting at 3.2 K/sq feet. It went up to 3.6-4 K/sq feet by late last year. I bought a site in adjacent BCMC layout in mid this year @3400 Rs/sq feet. Today, I heard from locals that a west facing 60 X 40 site was sold at 4.4 K recently .
Each time there is a transaction, that becomes the base price for future transactions. Sellers will expect at least 100 Rs more than previous transaction. Since there is demand across BDA approved layouts along Kanakapura Road such as Narayana Nagar, Judicial Layout, BCMC layout etc- looks like prices are going up quickly. Resellers are playing their part in jacking up the prices too.
I think BCMC was tracking around the same price as Narayana Nagar 1st block (assuming sites are same distance from main road/same facing etc). 30 X 40 would cost even more than 60 X 40 and north/east facing sites are costlier by 50-100 Rs/sq feet.