Do you guys drive around with your windows open a lot? Do you have the in-cabin microfilter installed? I rarely have my windows down here in TX and have the microfilter and my interior stays amazingly dust free. I have brick/black, but I would still see it on my dash and other ares. I rarely have to dust and when I do, there isn't much there.
I have the same issue keeping it free from smudges, scuffs etc. I clean it almost daily. I find that if i use a damp cloth rather than a cleaner that puts a shine on the interior it stays smudge-free longer. It is a little harder to get the marks off this way but then every time you touch something it doesn't leave a print. For the tough smudges I use Armor-All cleaner wipes. I only use them when necessary as they have alcohol in them and are not so good for the inerior. I just yeaterday used the Zaino Leather in a Bottle on my interior. I like it, but it does put a coating over the leather and seems to make it a bit shiny. I had to be careful not to miss any spots on the seats or you could tell the difference.
Even thought it's tough to keep clean, it looks sooo nice.