I don't have a recipe, but I have a minor ingredient note to throw in:
Peated Malt and Rauch malt = very different ingredients.
Pretending this were an all-grain recipe, you would likely use 2-3
pounds of rauchmalt to get a fairly strong smoke presence. However, if you used peated malt, more than 2-3
ounces would get out of control.
Many people have called Schlenkerla a bit of a "bacon beer" in reference to its taste. So my hint, as to a recipe, would be that you will probably want to steep 2-3 ounces of crushed peated malt, I would say absolutely no more than 6 ounces, TOPS.
I say that you will want to use peated malt
because trying to use the amount of rauchmalt necessary to get a good smoky presence will result in a couple pound grainbill, which approaches partial-mash territory, and you mentioned specifically extract, which leads me to infer extract plus steeping grains. If you were planning a partial-mash all along, then I'd go with the rauchmalt for the authentic route.
Now, hopefully someone else can help with the rest of the recipe - I've never done a bock, nor been a huge bock fan. (I likes my bitters and my porters too much.
)