That trunk paint is pretty sturdy for what it is if it's OEM.
If redoing it to stock specs, Zolatone makes a suitable replacement for stock black semi-textured coating. It's thicker than regular paint, but still retains a slight spatter pattern/texture to it. Not cheap at 58 per quart. Doesn't come in spray cans. Of course, if you want to do it a slightly different way, you could cheat and use say, the Delco brand spatter paint (has pretty good reviews) for older trunks as it has aqua and/or black gray speckles in it. Then just paint over that with a semi-gloss black or something.
Here's the zolatone:
Black/Black - 20 Series Stock Color Spatter Finish, Quart
tcpglobal.com
Of course, there's always the truck bed coating stuff.