I have tried in three different modalities:
(1) I asked my OER who specifically responded "we do not give out information of other owners" and then went on to describe how they are monitored closely and that this information - if disseminated - would qualify.
(2) I asked Jack at the service station and Jack, being the tremendously nice person he is, simply said "there are quite a few" and I said "how many exactly and he said "there are quite a few" - lather, rinse repeat.
(3) I have asked each store person I have come in contact with - from Houston to Austin to Toronto - and they answer "we don't get that information"
If you look back at the news, you will see that Tesla is very careful in disseminating the number of cars they have produced, particularly per week. The one glimpse we got was the re-call that occurred late last spring that involved cars manufactured between "A"date and "B" date and it was "X" number of vehicles after which, the math gave a number of how many cars were produced per week.
I would like to go to Jack and say "how many Teslas are in Texas" and have him say, 1,392 with 339 in Houston, 315 in Dallas, 199 in Austin and others spread over the state (those numbers are imaginary, by the way). But I doubt that he (or anyone) is going to do that.