Movement trays have been around since..umm...guessing.. during the 1990s? There a dozens of wargaming bloggers use movement trays. DeanM WAB Corner , Christopher Bunker Hill , Cyrus Bucellarii and Rob Hawkins hobby blog are all influential...well to me anyway :o)
Movement trays are a game-changer for large-scale wargaming, drastically cutting down the time spent pushing individual models and keeping your ranks crisp. They are especially useful for "horde" armies or "rank and flank" systems like Warhammer and maybe DBMM?
I use DBA-DBMM elements with my movement trays for Command Colors Ancients and Impetvs army units. Also I think, is one of the best ways to maximize your collection of miniatures without the nightmare of rebasing figures! :o)Impetvs 15mm frontages are 80mm one can use DBA/DBMM army elements to form up Impetvs battle groups depending on unit type i.e. Pikes I would use as a typical full strength Macedonian Pike block 2 by 4 (total 8 elements)
The elements can be removed during Command colors ancients and Impetvs games as casualties.