Thanks for all the input everybody. I think I'm leaning heavily towards the V10. His asking price for it was $12.9K but I reckon it could be bought around $10k.
I drove the 6.4l today. It seemed to drive ok but the dash was reading out 9.5mpg and the regen thing was coming on a lot. The truck has also been beat-on pretty good, those were a hard 110k miles, so their asking price is probably in-line with its condition.
Mowingman: Great looking F250 and good price but I'm looking to go totally debt free this year so am aiming for a lower priced truck. I'll be putting a landscape or platform stake body on whatever I get so the reason for going 1 ton is that with the setup I'm hoping for the 3/4 ton leaves me about 1700lbs extra payload for grass, etc. and the 1 ton gives me about another 1500lbs. I just like the idea of a little extra cushion when staring down the long arm of the DOT Nazi laws.
Also, I rather like having a manual trans, every vehicle I've had with a stick I get much better mileage in than an auto. Even the Stang is getting about 20.5 in the city and Ford only rates it at 17.
I'll keep this updated once my truck sells and I pick up something else. BTW the '07 Isuzu NPR Hd dump I'm selling is still available. My buyer I had lined up is getting a little flaky and I think the deal might fall through.