Still working on a low/no magic variant of these rules. I've spent some time reading from other sources for a realm level campaign (i.e. mighty empires) and tactical level warfare simulations. Games Workshop has a couple of rule sets that are fun for miniature play (Warhammer Ancient Battles, Warmaster), as well as DBA and FoG rules. However, even though these are fun to play FtF, they do not translate well to PBeM.
"Lost Battles" is an excellent read (by Phil Sabin), and does offer a historically accurate simulation for ancient warfare in the grand tactical scale, and the mechanics could easily be "automatically" processed in a PBeM format. For those of you interested in ancient warfare simulations and what can be learned from them, it is a must read.