I always wished that I can express my views to my friends in my own language but seems that typing Hindi from mobile is very difficult. If can type it smartly then I will love to see.
If u c from ppl's view then I don't think they want Hindi keyboard, here in India people boast abt their english abilities.
So it may not see that much logical.

Nice question Mr. Mujju.
I have rather my own point of view. I have been a qwerty keyboard lover ie. everyone I had was having qwerty keyboard, still I am not much into sms sending.

Hindi has lot more latter than English.. Just to tell here that I can type Hindi as well as English at equivalent pace.

Lets have a test..

Mujhe Hindi aur angrezi dono likhna aata hai.
मुझे हिन्दी और अंग्रेज़ी दोनों लिखना आता है

For first line I had to hit keys approx. 45 times
For Hindi I had to hit keys 40 times but still I am so used to typing English that I felt comfortable writing in english.  So Hindi really saved few of key strokes but its little complicated to write, you have to actually think for combination of keys before making words.

So as Lurker said, if it qwerty and hindi is supported then I will love to do it.
Ya, in rural area or people preferring Hindi it can be a nice move as I hv seen this, people using Hindi as their preferred language in such areas. May be same will go with Hindi..
Provided that they it is in standard typewriter    form.

Ya ofcourse I have seen phones with Hindi input.
But no qwerty phone with Hindi input.

Hi I have seen hindi input phone too but never used to write anything.
I don't think they have predective text in them.