The class $\textrm{NC}^i$ is the class functions computable by circuits families of bounded fan-in, $n^{O(1)}$ size and $O(\log^i(n))$ depth. The $\textrm{NC}$-hierarchy is the union of those classes.
Is there any study of the linear-size variant of this hierarchy? That is circuits families of bounded fan-in, polylog depth and linear size?
I know their exists some work with linear-$\textrm{AC}^0$ but nothing else. Remark that at least linear-$\textrm{NC}^1$ is nontrivial since it contains regular languages (and thus some $\textrm{NC}^1$-complete languages).