I think its safe to say that we're going to see a lot of issue crop up with regards to 64-bit support, and its going to be difficult to sort out which ones are due to issues in the kernel and which ones are due to issues in third party programs compiled via pkgsrc.
We've only just begun trying to run larger pkgsrc apps on 64-bit. The bulk build mechanics work very well and the build system doesn't crash even under extreme bulk-building loads, so we have definitely cleared a number of major hurtles. -Matt