Rauch malt is LOVELY - you can go 100% and it's amazing IMHO... Thrifty are cheap for it too, I got 6kg, used 5.5 in my schenkerla clone and the last 500g in my rsmoked rye stout that's in the FV at the moment.
I'm tempted to try some peat smoked sometime but as Steve says it would have to be a small amount... oomph it up with a smoky whisky instead maybe

or go proper filth/cheating and add:
http://www.bushwear.co.uk/nostyles.php?ProductID=346928
The jury is out it seems on whether Adelscott use all beech smoked rauch or a little peat in their 'scotch whisky beer'
You could always smoke your own: the ProQ gives some options for wood type and is convenient:
http://www.forfoodsmokers.co.uk/acatalo ... rator.html
This book is well worth a read for how to and recipe ideas - I think it's the best in a fairly patchy series:
http://www.amazon.co.uk/Smoked-Beers-Hi ... 484&sr=8-1
Smokiness can be defined - some stuff is lightly smoked other stuff just reeks of nowt but smoke! (Think of cheeses / ham etc. Personally I like it at the ridiculously smoky end of the spectrum...) ... am sure there's a 'scientific definition' that's the equivalent for scoville units in chillis somewhere but dunno what it is.