Hello Johnlin, welcome to the forum
(is it the winter approaching or are there many new members here? at any rate this is a good thing! the more the better)
What you ask is quite hard, Ardbeg 17 is special and pretty much unique in flavor profile. There are a few whiskies that popped up as RELATIVELY close to its profile, but none is as close as say Macallan 10 CS with Glenfarclas 105. Therefore, the best suggestion is to order more at the Ardbeg site right now cause they will be gone very fast.
Ok, these are the ones that came out closest to the 17.
Ardbeg 1977 (again... I know) -more rounded and balanced, slightly more clean and dry peat. More dry and less sweet then the 17-
Ardbeg 1990 9Y OMC -Less sweetness and more malty with more oak and feints.-
Ardbeg 1994 SMWS 33.51 -More peat, more oak, more estery/fruity and less feints and body.-
Ardbeg Committee reserve 2002 -More peat, more honey, more oak, less salty/medicinal, less feinty, less nutty/oily.-
This may be of not much use because most of this is either hard(er) to find or expencive, I know but then again the Ardbeg 17 is a class on its own.
A last suggestion perhaps, not quite the same league as the 17, but Bruichladdich 3D peat proposal (first edition 3D) and Benriach Curiositas 46% just might do the trick for you too. Both are quite balanced and sweetish with enough peat to keep you interested, just a thought.