I know UOSteam has built in mapping and shows party members, but not everyone uses UOSteam. My friend for some reason cant get UOSteam to run but Razor is fine so we use UOAM.
I was just looking around at a cheap VPS that would host one but then thought, it would be a lot easier suggesting it here and have it hosted on the same server as shard/website etc as it would of been for UOEvo.
It should be relativity easy to setup once the server application is tracked down (Better suited than the client for hosting it) and hardly a resource hog.
Would be nice, not only to see who is where so you can avoid taking a trip to a camp spot to find someone is there, and to generally team up and do stuff.
There is the downside of PK's seeing everyone in fel, but that the risk you take connecting to the server and then going to fel 
Just a thought 