The A'bunadh is a cracker, there is batch variation so just be careful as they are not all going to be the same.
Basically; these are aged only in Oloroso sherry butts and are not chill filtered. So you like 'em big and spicy.
The first thing that springs to mind would by a Glenfarclas 105. This is also a NAS whisky and bottled at 60% from sherry casks, it's also around the same price as the A'bunadh so would be a good starting point.....it's also brilliant.
Head towards the heavy sherried stuff from other distilleries like GlenDronach, Benriach and Glenfarclas.
The GlenDronach do a series of single cask bottlings which are from sherry butts, not chill filtered and bottled as cask strength and are very, very good.
Benriach use a lot of sherried whiskies and are also very good.
Glenfarclas do a nice 15 year old, which is chill filtered and only around 46% but it's heavy on sherry.
Retail for these bottles are between £40 and £60. The GlenDronach single casks are worth spashing out on.