I have to politely disagree with the suggestion. Quite frankly I believe that FreeBSD already has such a support model, and a working one at that.
When looking at the
10 version you'll notice that it got released in January 2014 (source:
FreeBSD release information), in the mean time we've seen 3 small "side releases" (
10.1 to
10.3) and that's basically it. Now, if you look at the
FreeBSD support cycle you'll notice that
10.3 gets supported until April next year (April 2018). So that's effectively
four years worth of support for the
10 version. You were saying?
And let's be honest here: even on Linux an LTS version requires updates from time to time. I've been using several of them and the only thing which matters is that you don't have to perform a major version upgrade. Yet, as shown above, the same applies to FreeBSD.
Another important difference; in my experience a Linux LTS isn't really an LTS. It's simply a version which receives (security) updates and that's basically it. Yet the moment when you need to upgrade you'll come to conclude that the LTS is merely a "version freeze" while other development still went on. More than often effectively resulting in the inability to upgrade from one LTS version to the other because you're basically skipping several major OS versions by doing so.
FreeBSD on the other hand supports one version for
years, while also making sure that the gap between versions doesn't widen too much (basically only 2 versions are supported). Resulting in the need to do a major upgrade, but one which has been calculated for and which is also fully supported by the system. That is of course no guarantee that nothing can go wrong, but it
is a guarantee that if something does go wrong then you won't be looking at the need to install 4 or 5 versions in order to upgrade your system because of the massive underlying changes between those versions.
FreeBSD doesn't need a change in its support model because it's doing an excellent job so far and in my opinion even better than those on Linux. The main thing is that you simply need to adapt to the way it works and use it as intended.
(Edit)
Another very important thing here, which I think you're horribly overlooking, is the reason why you need to upgrade. That's not just for fun, but also for your own safety as well. Sure, it can be a drag. But it'll be more of a drag when your system got overrun because you were using something which contained exploitable bugs.