It's uploaded but won't be publicly viewable until midnight Wednesday (23 Jan), at the earliest. I'll try to either resist any immediate revisions or get them in before the point when it will delay the process. When the link goes to version 4, with a 2013 date, that will be it.
I had hoped to have more relativity in this version, but I'm having to hold off on the more rigorous argument, for the moment. I hope it will come along fairly quickly, and then I will do an arxiv update again and submit to a journal. I don't plan to submit this one. Apart from it probably needing a lot of writing improvements, I have at least one major section in work to add, that I hope will make the entire thing much more convincing.
The specific argument that the magnetic force is the anti-Coriolis force predicted for the lab frame by the test-particle rest frame obserever, who sees the lab frame Thomas precessing relative to the source particle rest frame (where the interaction is purely Coulombic) , is only a couple of days old at this point. Previous arguments have always resulted in additional cross-product terms that I tried to subsume into the relativistic electrodynamics, with limited if any success. This new argument yields explicitly just the magnetic force. I also used to think (and say) that the anti-Euler force had to be part of the magnetic force, and was involved in the hypothesized subsumation of the extra terms. That now seems unrealistic, and instead I now think the anti-Euler force part at order v^2/c^2 is a new force. I guess that generally the anti-Euler force at higher order in v/c corresponds to the weak force, but I think that the piece at order v^2/c^2 may be overlooked until now. The form of it is explicitly provided in this new version.