Hey redivivus,
Just from looking at other applicants going through New Delhi, they generally request the passport earlier on in the second stage process.
I think there is a New Delhi thread where you may be able to get more specific info, but just looking at June, for example- someone got sponsorship approval on the 1st August, then the PPR request came on the 24th Aug. I am not sure if it comes by snail mail or email- it may vary depending on the applicant. I know generally speaking the New Delhi VO is quite fast, so you may possibly get the VISA before Christmas if you case is uncomplicated, however I think things such as request for interviews or what not might delay the process, so it's really hard to say. Hopefully the New Delhi thread might have some more specific answers for you.