Peterson may well re-issue Durbar, even when Dunhill owned it the supply of Durbar was spotty, I don't think it was ever in anything resembling continuous production, I think they made a production run every 5 years or so, and it was slightly different every batch, with more major differences when production shifted from Murray to STG.

McConnell Oriental Square is about as close as you can get to what you would consider Dunhill Durbar, at least until such time as Peterson orders another batch from STG. Oriental Square is based on the 60s-70s version of Durbar, iirc McConnell made it for Dunhill back then. Supposedly they still had copies of the blends, though many of the oriental tobacco varietals don't seem to be available anymore, its all homogenized into "turkish leaf". But knowing what was in it and how they were cured and cased and pressed etc goes a long way to knowing how to reproduce it with today's leaf.

That said, there are a number of other readily-available longstanding blends that are in the neighborhood of Durbar that you should probably also try, they won't necessarily be "Durbar" but they will be in the neighborhood and may well scratch that itch. McConnell Original Oriental is one that I like about as much as Durbar and the one I always reached for when Durbar supply was spotty, other is Balkan Sasieni, also Rattray Red Rapparee, Robert Lewis Orcilla, and the trinity of oriental blends from L. J. Peretti (Royal, Tashkent, and Oriental #40). Peretti still has a source of oriental varietals like dubecq, yenidje, xanthi and drama, and they make some of the best and most old-school oriental/balkan blends available today.