Hi An,
I'm not opposed to the idea but it would need to be implemented for all 5 data layers before it could be included in mojoportal. I suggested the config approach because its easier to implement, but I understand what you're getting at, the config approach becomes unwieldy if you are setting up lots of sites. I think it would also be important to encrypt those settings in the db.
The thing for me about the multi sites feature is (at least if using multi sites by hostname), its a very limited solution if you have important sites, they should be separated, because as soon as you need SSL for one of the sites it needs to be separated because only 1 SSL certificate can be bound to port 443 on a given ip address. So I tend to favor the easier config approach because I really don't see it as a great idea to run a bunch of important sites from a singler instalation, though I know some people do it, I don't do that myslef. Maybe in folder based sites I can see it because they all have the same host name and can use the same SSL certificate.
In any case, as I said, I'm not opposed to a db solution, the problem is we can't just do it for one db, it has to be implemented for all of them at once because its a core feature. So its a good bit more work. But maybe if you want to implement the MS SQL version I can get ot the others, but I'm pretty busy with other initiatives.
Best,
Joe