Sounds like you need this quickly, in which case Stillwater is a good choice. The NightStalker Black or Green would both go well with a maroon dress, but they are not traditional tartan designs (rather they appear solid, unless you look closely), so you have to decide if this is your comfort level or not. I have a lovely mini, made by AlanH in Lindsey tartan which is maroony, but I'm not sure where to get one quickly in this tartan. Black Watch would also go well, and is usually easily available from many folks.

Be well,