Check out stepside454's truck here.
http://www.67-72chevytrucks.com/vboa...d.php?t=260752
That is one of my favorite stepsides. If you don't like the looks of that truck, then you probably just aren't a stepside guy. If you do like it, there's probably a few little things you can do to yours that will drastically change the look.
If I was in your position, I would go with some standard offset 15x8 chrome wheels, some tires with a taller sidewall, like a 275/60/15. I would also find a good stock grill with the bowtie emblem. I think a black 78 grill with the yellow bowtie emblem and the aluminum trim across the front would sit really well with the light colored paint job.
Your truck looks really nice though. These are just a few of my personal ideas if I were to build a similar truck. Maybe you might consider some of these or they might get your own ideas flowing to get the look you want.