There is 12(!) different colors by now, but obviously that's not enough in the long run. It's difficult to find very distinct colors without making them all shiny and annoying. Feels like I'm back to EGA times, 4 more colors to spend, and one of them is given to squad AI already. There also seems to be a bug that the map marker colors do not stay that well in sync with the field/edge marker colors.

OzyThesage's suggestion about the shape might be the way out here. Initially I was thinking that it would make them appear distracting and inconsistent, but maybe it doesn't matter that much in the end.

And yes, jeep is #1 currently.

As you may not know yet, your soldier is in a block which is active, everything is rendered.