Holy Cow! ANOTHER sane Linux supporter. I did not even knew they existed! I dont know if you have seen the usual Linux supporters here, but the debates with them.... are quite strange.
You are the fourth person I debate with, so this might take time as I have work to do. I will use Round Robin, or I should just drop the FUDers and talk only with the sane Linux persons.
You say that there are not much interest in SMP workloads such as databases. That is strange. RedHat, Suse, Novell etc all of them wants to make money. The big money is in Enterprise workloads, such as Databases. We all know that Oracle made a fortune in databases.
Thus, I am not convinced in your explanation "there have not been much interest". My interpretation is that Linux kernel devs can not handle that kind of work load, they dont have the servers nor experience of building such servers. Oracle, IBM and HP has.
To build a cluster is easy and Linux kernel devs can develop for them. But not for SMP servers costing many millions of USD.