Suppose I print an eight-layer PCB, with a spiral starting on the top layer and continuing through all the inner layers to the bottom. Assuming I keep the spiral turning in the same direction on all layers, this PCB should act as an inductor. (I could leave a hole in the middle of the spiral for a core, or if not, I could simply leave it air-core. I'm assuming air-core for the moment, for simplicity.) Many calculators are available to determine the inductance of an air-core choke, and to determine the ampacity of copper traces at given weights and widths on both inner and outer layers. The naive design of such an inductor is straightforward.
What I'm wondering about is non-obvious effects. Will the inductance actually turn out like an wire-wound air-core choke with equivalent dimensions and numbers of windings? Will there be additional heating effects due to magnetic coupling between the layers, or between the PCB and any nearby metal? Will the magnetic effects cause physical stresses on the structure of the board? Are there any other reasons this might turn out to be less of a good idea than it seems at first?