That is what I had in mind :) Actually, I want to start in Sri Lanka - been going to a great Sri Lankan restaurant here in Berlin that has a picture of Sigiriya, which I've looked at so many times that I need to see it in real life now :)
Definitely want to visit either Chennai or Bangalore, Mumbai and New Delhi. Maybe also Hyderabad. I'm still not sure whether I want to travel through more cities and spend less time in each, or visit fewer cities but have more time and experience the city in a less touristy fashion.
Well, I hope to be able to check my email at least once a day, but most hostels seem to offer wifi. For real working I plan to visit co-working spaces, though.
Thanks for your input, it's good to hear some real life experiences :)