If you put in a call to Delta...they will discuss with you what can be done and will do the cam whatever way you want. If your truck's a daily driver then IMHO you really don't want to get too wild and crazy with it's cam.
IMHO..one of the biggest complaints about the stock G180 is it's lack of low-end torque. The ones I have owned all developed the majority of their torque and hp in the 3000rpm-5000 rpm range, so by getting your cam reground to assist in getting more muscle out of the 1000 rpm - to 3000 rpm range would probably be a good place to start.
Delta cams are very familiar with the Isuzu G series engines and have a lot of experience with re-grinding all types of cams for them, so investing in a few minutes on the phone with them on their toll-free line discussing what mods you are doing to your engine before you send in your old cam to be re-done always pays off.
http://www.deltacam.com/