It looks like Sri Lanka Telecom has decided to provide its ADSL service to the residents of the Kadawatha area from the 10th of February 2007.
How do I know this? The www.slt.lk site provides a form where you could submit a phone number and find out if the ADSL service is available for that number.
Today I got this this when I submitted my home number:

Finally, I can stop emailing SLT asking for ADSL for my home!