Forget about the Taj - it was ok with kart specs dating back to the early 90's, but you'll need nerves of steel to race a 30hp+ kart there now. Forget, also, about Isurupaya. The track was probably the most fun I've ever raced on, but again, the speeds with the current karts will render the track very dangerous, especially on the downward slopes.
The BMICH was probably the most boring track, but the smoothest. It's probably the only track I did not break a sprocket! It'll require a bunch of guys with brooms sweeping it as it often has a thin layer of dust - extremely slippery with the slicks. Even on raceday, when the racing line was cleared after a few laps, this film of dust made overtaking very dangerous, as the moment you drift slightly off the racing line, you are bound lose traction. If you guys are able to get permission to host some practice sessions, and perhaps a race, it could be the start of the karting revival!
Wasn't somebody supposed to build a proper karting track just out of Colombo at some point? If I remember right, there was an attempt by SLARDAR or one of those organisations to host some races on a purpose track...again, a lot of smoke and no fire??
There was also some carpark near the parliament that was used more recently. What happened to that? Never raced there, but it was supposed to be quite fun.