Tim asked: Will this hotfix be back-ported to Exchange 2000?
No, I'm sorry to say that there are no plans for this. Exchange 2000 is past its extended support lifecycle. The only fixes from now on for Exchange 2000 will be if security issues are discovered.
You do raise an interesting point: while this problem has existed for a minority of Exchange 2000 customers, most of them haven't had kernel memory issues. Why are people suddenly running into this after upgrading?
The reason is that a flood of new features, hardware and clients have come along in the last couple of years. Multiple upgrades tend to happen all at once: new drivers, more memory, bigger disks, more users, additional client applications...all of it adds up to more memory pressure.