Robert Everson has some interesting new HO decals, but these aren't for a livery...read below
Lexan Body Wheel Opening Cut Guide Decals
"Looking for a quick and efficient way to trim out the wheel openings on your lexan bodies? Here it is! Wheel opening stencil decals for lexan bodies. There's enough decals on this sheet to do 6 cars. These waterslide decals work excellent as a guide while trimming out the wheel openings of your lexan bodies. There's 4 different sizes to work with on this sheet as pictured below. There's 2 radius lines per decal, each being the size indicated on the sheet. You can lay your tire over the different sizes to determine which size works best for you. Even if you want a wheel opening shape that isn't perfectly round, these make a great refence to do what you want.
There's also a centering crosshair at the center of the radius to assist in placement. One use of the crosshair is to mark the length of your wheelbase with whatever works such as a permanant marker, then place the crosshair over your mark. You can get creative here!
Last, there's a slight curve above wheel opening stencil that can be used as a guide for the height of your wheel opening. You can refrence the curve to a straight or curved body line at the top crest of your body panel for more accurate placement."
Go to the website and check it out. The entire above text is from Rob's site.