Since I didn't post the initial photos here when I complained about the color to the guy...here they are (including a comparison of black vs another inkjet piece from mamemarquees (the VS CLASSICADE marquee) to demonstrate that inkjet CAN do proper blacks...
First up is side art contrasted to my semi-gloss black paint on the cab:

As you can see...unacceptable.
The next is the side art contrasted to mamemarquees work. Note that the marquee is made of the higher quality stuff scott offers, as such, it's hard to get a nice photo of it as there tends to be a bit of glare...but you still can see the difference:
