When I needed to do a repair on my ex-Norm Whittle "Eagle", I tried to peel off the graphics in a small area. It was Monokote of some sort, applied to white epoxy paint, probably K&B Superpoxy, and sealed down with Monokote trim solvent. Could NOT get the stuff off, even using trim solvent, and it was NOT clear coated. My opinion is that Monokote isn't a bad option for graphics and numbers, especially when used with trim solvent. And you could clear coat over it if you insisted.
Steve
Someone in the Forum cuts his own lettering and graphics using Monokote. He does really good work. Can't remember who. A red and white Mig comes to mind.
So yes, that could work and probably work quite well.
However, and I've been saying this for years, just go to your local sign shops and ask them to save their vinyl scraps. They will be free.
The quality of vinyl material will probably be better and you can eliminate the trim solvent around the edges.
Also, just a tad of heat and vinyl can be removed easily to replace or change. 3M makes a product to remove adhesive quickly without damaging the surface.
As far as clear coat, they do look better under a nicely applied clear coat, my opinion.
I always cleared my models because it's easier to clean them. I've been using vinyl on my models since 1996.
The modelers who use my graphics, who compete in scale events. always clear the model and the graphics.
One last thing. Colored "trim sheets" are available at HS and Hobby Suppliers. They work but the adhesive used does not hold up over time. Unless they have been improved?
All these models sport my graphics or paint masks. Everything is custom made for the model, especially the Warbirds and scale models.
Take a look! There are some contest winners there!
http://www.rcuniverse.com/community/profile.cfm?section=gallery&memID=11343&pageon=1