Can users pick their access level for themselves?

I have a HUGE blog with tons and tons of content. Not all of it is relevant to all users, and I’d like to help them weed out stuff that isn’t really their concern. It’s not that they shouldn’t access it, it’s just that I don’t need to drown them in irrelevant information. I’d like to, therefore, allow them to choose their access level for themselves, and even switch between them at will, out of available ones (I, obviously, don’t want them to be able to choose admin levels and other restricted access levels, some of them custom ones, too). I’d also like them to be able to pick several levels of access as the plugin does now, anyway, whichever way they like and prefer.

Is this possible yet, and if not, do you think it would be something you’d add later on? The plugin, the way it is, will take me a long way where I want to go, but that added feature would be very helpful in the future when the member count climbs.