I have one of the Beatles 78s: I should have known better/I'm happy just to dance with you (DPE 168) that I was lucky to find in a pile of old records at a raddiwallah. Got it for a song.
Some years back, my record dealer called me to say that he'd bought a bunch of 78s from someone's home, and that it contained 6 Beatles 78s. By the time I rushed to his place, he'd already sold them off to another dealer for Rs.10K each. Found out later that that chappie got a foreigner customer for Rs.25K each. These days, they typically sell in Bombay for 40K+, but are very hard to come by. Sightings are like UFOs - few and unconfirmed.
Most countries stopped production of 78s by 1959-60. India continued till about 1966, tho' there are rumours of Beatles titles till '68. Besides India, Venezuela and Philippines also released Beatles 78s, but the titles (and numbers) in those countries were much fewer, and almost impossible to find today. Which is why the traction in Beatles 78s is largely restricted to the Indian titles. Typical prices on eBay these days is $500+, irrespective of condition.
One possibility remains: there ought to have been other pop/rock acts of the early 60s that were also issued in India on 78. You do see plenty of Cliff Richard titles - I have a few - but what about the Rolling Stones, The Who, Hollies, etc, that were released contemporaneously on 45s? Any sightings? I once spotted a Beach Boys Indian 78 on eBay. Many of these might prove to be almost as valuable as the Beatles 78s, especially for the period '64 to '66.