I have a 4x4 crew cab long bed, 6spd man and it was exactly what I was looking for myself. Is this truck going to sit if you are not pulling the trailer, or is it going to become your daily? I said that i didnt need a Crew Cab, but I tell you now that I have the space, I sure darn use the crap out of it.
I dont think there would be much difference between 4X2 or 4X4 besides the fact that if you ever have to park your racing setup on the grass at races, you might want the 4X4 to get you butt out if its soft. To me iit looks like 4X2s sit lower so you probably wornt be able to go up a tire size without a lift.
Transmissions, I have a 6spd man and I like it. I think its a great trans eventhough reverse is in an odd location. In a manual you will have to do some shifting, but you have alot less that can break, or overheat if you tow heavy.
What weight do you plan on pulling?