every work around I've seen has issues.
1 - put a thin line infront of your wall types to represent paint finish.
-advantage. you can tag and filter in plan. All wall finishes for one level of a building can be shown on one plan.
-disdvantage. you're giving yourself a head ache editing thing if the design is still subject to change. multiple walls to move/edit/join for openings.
2 - use a 2D detail line family in plan. eg the 2d detail family contains several line types of different colours. you can stretch the 2d line to suit the wall length in plan.
-advantage. its a family. you can tag and schedule it. All wall finishes for one level of a building can be shown on one plan.
-disadvantage. the 2d family isn't linked to anything in model. someone can paint the wall a different colour to what the 2d fam represents causing contradicting data. Walls move and get deleted during design development. if one 2D family isn't locked to a wall or someone neglects to check the drawings/misses one. incorrect info can be sent out.
3 - a 3D view of each room.
Advantage - you can tag painted wall materials in 3D.
Disadvantage - Every room will need its own 1 or 2 3D views. Rather than been able to show all wall finishes on one level, on one plan.
4 - every room has its plan view on a sheet. surrounded by its internal elevation views.
Advantage - you can tag painted wall materials in elevational views.
Disadvantage - Every room will need its own sheet. Rather than been able to show all wall finishes on one level, on one plan. This will vastly increase sheet numbers to awkward amounts to manage.
No method is perfect. everyone has issues. We usually lean towards the 2D family but as mentioned you have to keep on top of the inherent issues with that.
One other promising looking option is the video below for a plugin i came across trying to look for solutions for this issue. (called ARUtils).
https://www.youtube.com/watch?v=W3I1iav6ucs&feature=youtu.be
Yet to try the plugin (waiting on the 30 day trail activation file) but it does make me think. If they managed to find a solution. then it is possible to do paint tagging in plan.