I liked how on Fallout NV it marked your companions on the map. Not sure id consider the horse a companion or not but id really like to know where the hell Lydia is, or in your case shadowmere.
Yeah, that would be awesome. On some quests you know where people are, but in general you have no clue. What may be neat is to use the courier perhaps? I mean, other people in the game can send messages to you to get stuff done - why can't it be the other way round?
What if the courier had a "home branch" and you could have dialog with them along the lines of:
1) "How may I help you?" (NPC)
2) "I'd like to find someone" (player)
3) "When I get your message, I'll deliver it in an instant!" (NPC)
4)
(player choice)
5) "I'll dispatch the courier right away. Do come back." (NPC)
And then maybe at some point the character would find you. Wouldn't work with characters that are stationary in some place because of a quest though. Perhaps in that case the NPC would say:
"Well, I'll see what I can do, but people have mentioned they were seen at "
(then map gets updated and miscellaneous quest gets added perhaps)
That could also apply to non human creatures, such as Shadowmere. Only characters you have encountered and characters that can actually be found would be included on the list. Dunno, my random thought on it - I guess what I'm getting at is that it could be built into the game dialog rather than just markers straight out.
Wouldn't work in some cases if the target is constantly moving if they have a job to do.
But using the couriers for your own use would be pretty cool - I mean you always get quests from people, what if you could give quests to other people (like deliver this package for me). Then maybe they get killed, package gets stolen and then you have to get the package back.
Sorry - taking the thread in another direction!
But yeah - ticks me off with horses and the original post as well! 