Hi Zeropanic:
I asked a similar question about brewing a roggenbier using Northern Brewer's rye malt extract and got no response. The NB rye LME is only 30% rye and 70% barley, so it really would not work. I have not seen any other extracts out there that are pure rye, or a higher percentage. Regarding use of NB's rye LME, I just posted by experience on this thread:
http://www.beersmith.com/forum/index.php/topic,8187.0.html