I've been dissatisfied with the version 1 markers I made to show "bunker" units in FoBWW2. The version 1 marker was 3" wide to match the unit frontage, but beyond that it didn't do much visually for me. Its the small piece in the photo below.
Version 2 is made to just drop the infantry unit into the marker...and bingo! Instant dug in/bunker status. The entrenchment is made of 3/4" wide quarter round epoxied to a plastic base. I think they're a big step up in appearance. AT guns will use the same thing, but adjusted to fit their stand.
I've sketched out a similar construction method for things like ACW entrenchments, horse and musket redoubts, and WW1 trenches. I'll be making some up to see how they look and work.