The carpet on the doors can take a lot of abuse. Hit with boots as you get in & out, mud, snow & the chemicals used to melt that, etc. I've seen guys put vinyl there, but unless all you were is JC Waterwalkers, sneaks, or are barefoot & live below the 37th parrallel, I can't see that being very durable for any length of time. Show trucks or occasional use trucks would be O.K.
I've dyed carpet before, but it makes the texture kind of stiff. If you're O.K. with that, why not get some green carpet, tape off the camo pattern that you like, & dye the carpet like that. I think that you would only need one aerosol can each of a lighter green, & black. How long that would last, I don't know. But it would certainly be different. If it doesn't last, the carpet to be replaced would be a minimal amount. An upholstery shop may even have some cuttings large enough if the camo idea doesn't work out.
Another idea would be to cut out interlocking pieces of carpet in the different colors of the camo pattern. Like puzzle pieces. That, I would glue to a piece of scrim backing. What you would be doing is making your own 'roll-stock' of your own design. Then cut out the shape of the carpet pieces, using the old ones as a pattern. Glue the snot out it when putting the carpet on the scrim. You could only do this using cut-pile carpet. Loop carpet would not work for this.
It's just an idea, & I've never done this. But it wouldn't be the first time someone told me that something couldn't be done, & I did it anyhow. Sometimes my experiments don't work, lots of times they do. If you don't push to edge, how are you supposed to know where it is?