Guys, please, you are my only hope now :P . There was a very old mod, which stopped working recently and since there is probably no way of fixing it, maybe you'd consider putting such functionality into XVM? Of course, if someone doesn't need it, it can be turned off, so voices against it are not appreciated ;) .
Additional options that i can think of is similar gun elevation/depression indicator and hull tilt indicator - those two could also be useful (although probably not as much)
Original mod file attached to this post, if someone wants to decompile it.
Here is some random screenshot, with gun constraints :) for a TD - such mod is crucial if you disable camera constraints in sniper mode (like with PMOD, or other mods), but of course for turreted tanks traverse indicator is also very useful, i became heavily dependent on that :( ). Graphical design, although not very appealing, was surprisingly useful: