You might need 500 hp in 4wd though. A V10 4x4 is more than practical, if you have needs for it. My family farms, so I can think of uses for that. When it's muddy, hauling cattle in a pasture, you need some serious horses to get all of that weight through the mud. We had in a truck a 30' goose neck trailer with a little over 16,000 lbs loaded onto it. We had to take that weight over rather recent terraces. 4x4 was needed because of how soft the ground was, and a lot of horsepower was needed, because the trailer was hanging up on the terraces.
So you can't think of any uses for the V10 4x4, because you don't push your truck to the limits that the truck goes to. But here's another way to think of it.
Ram 2500 CTD 4x4. Look at the power that thing is pushing out, so why does that need to be 4x4? You aren't going to be spinning the wheels at 50+mph in 4x4. You need the 4x4 for keeping you from getting stuck, and all the power for towing.

 

My uncle has a F350 with a V10. He flat out did not want a smelly, noisey diesel that no one will work on around here. Most shops just won't work on diesels so that leaves the dealership and we all know how that can be...$$$$ and time consuming.
Anyways, he pulls a 5th wheel for camping and lives in upstate NY where there's lots of snow, so the 4wd is a must. I would take a Ford V10 over their v8 any day. Their v8's are gutless. On that note, i wouldn't want either of them....lol But his has 310hp/425ft.lbs 35hp shy of the Hemi's but 50ft.lbs more torque which is substantial when your towing a 5th wheel.

As far as going 50mph+ in 4wd. All the time on the highway. Just because I have my truck in 4hi doesn't mean I need to be going 35mph. If there's enough slip for the tires not to bind on the pavement, my truck goes in 4hi, why not. That's what it's for. i don't wait until there's 10" of snow to use 4wd. I had no problems doing the speed limit(65mph) or maybe even 5mph faster in 4hi granted there wasn't ice or 10" of snow.

 

+1, couldn't have said it better myself... There's nothing wrong w/ the CTD, but they have their place, just like a V10 does. And from a purely aesthetic point of view, NOTHING sounds quite as badass as a rumbling hot-rodded Viper V10.

 

oh yeah, gas engines have a nice rumble to them rather than those diesels which sound like something is clonking around in there

 

I don't like the sound of the vipers v10...sounds like *** to me. Don't get me wrong it's a bad engine but the hemi sounds a lot better. Take this one for example with a borla which is a awesome catback...still sounds like butt. I dunno if it's the extra 2 cylinders, firing order or what but if anyone knows feel free to chime in.

http://www.youtube.com/watch?v=UrJW_MMzBb0