In spite of all uncertainties, it looks like Delhi Marathon, scheduled for Dec 11th, is finally going to happen. I called up the marathon office, and they have confirmed that the event is happening. Promotions are going to start soon (and they will have to do it after the run if its not soon enough). It looks like the online registration link on their website (delhimarathon.com) may never be up, so if you are intending to run, just mail the form.
As for the Mumbai Marathon which I am intending to run (Jan 16, 06), registrations were supposed to start Oct 27th, then Nov 7th, but I am still waiting for their online registrations to start.