I think what you have down is pretty good for the time you have, although it would be more efficient for you to replace India with Thailand, and it would make a bit more sense as it shares borders Laos, Cambodia and Malaysia
You'd only have the time to get a small taste of the huge, diverse country that is India, and you'd have to fly there and get your visa beforehand (isn't a huge problem since they are valid for 6 months). There's also the recent trouble in Mumbai (like there is Thailand) so keep updated with the news before you go.
On a positive note India is a different experience from the other countries you are seeing and might be a refreshing (or intense
) change. If you end up doing this do some research on Delhi, Rajasthan (Jaipur, Udaipur, Pushkar), Mumbai, Goa, Kerala as these are the most commonly visited and enjoyed areas to narrow it down for the time you have.
[ Edit: Edited on Dec 5, 2008, at 4:15 PM by Erik85 ]