It appears that the pricing for BizTalk Server 2006 R2 has been announced, see here, although the main BizTalk site doesn't seem to have the information yet.

It would be interesting to know where the new pricing for Enterprise Edition comes from (35.000 vs 30.000 for BTS06 R1). I wonder if the licensing model is changing... Traditionally, BizTalk licensing has been tied solely to the scalability and performance possibilities of the Enterprise Edition (multiple processors + multiple servers per group). However, I wonder if this is changing in R2 and Enterprise now also brings features not available in Standard edition, because the pricing for the Standard edition doesn't seem to have changed at all!

BizTalk Server 2006 R2