Drew,
Yes...and no. On paper, sure, in the real world, no.
As I'm sure you probably know, HP is calculated using torque values ((RPMxTorque) / 5252) so yes, add enough RPMs and you can manipulate the numbers any way you want.
In your example what you're saying is take the 4000 RPMs, multiply it by 2.5, and at 10,000 RPMs the V10 will do the same job a big diesel does at 1,600 RPMs.
Possible? Well...maybe. Practical? Not really.
Again, that is NOT a knock on the V10. The V10 is a great engine, it's just not a big diesel.
Now...if Ford would develop a new, bigger Ecoboost for MH duty it might be a game changer. The torque the EBs are making at low RPMs is impressive. I see some of the new Class Cs are using the new 3.5 EB with great reviews.
My wife just bought another new Explorer. The last one had the NA 3.5L, this one has the 2.3 EB. The new one is 10 HP less, but has 55# more torque. This one is night and day better driving than the other one. More torque at a lower RPM, plus we're seeing a little better MPG. We're happy.