And what's wrong with six lug wheels?

There are lots of applications for six lug wheels. Toyota, Nissan, Chevy and some of the older full size Jeeps use six lug wheels and all are on the same bolt pattern as the Isuzu pattern used on the Luv.

I have Jeep Grand Wagoneer wheels on my Luv. I just had to bore out the center to clear the hub. They look good on it too and I got them dirt cheap. As for the axles, I heard the Toyota ones hold up quite well. Of course if you want 5 lug wheels, I guess you could put a GM 10 bolt under it as long as your tire size doesn't excede 35 inches.