That is a bit over-dramatic. Full flaps, without a lot of gas, 1000 feet is plenty of room to spool up. However, I think this is a very bad idea. Water is HEAVY, with its own momentum too. Stress at the wing roots will be amazing during pulls to level during release. I would bet even money you see a stress failure and a nice explosion soon enough.
We had an ORION once back when I was in VP-8 that flew all kinds of missions...bounces, tac trainers, ASW, you name it. Maintinence then discovered that the wing spars were cracked, in multiple places. Some of us got a little nervous after that.
Recently, the allowable hours on the P-3 airframe has been cut dramatically, due to the limits of service life being reached. We've already sent some to the boneyard.
I just hope we get a replacement before a crew has to die to accelerate the process. I love the old girl, but it's time for her to retire.
As for the 747-as-a-tanker, I'd have to have a LOT of questions answered before I thought it was anything other than a political boondoggle. The 747 is a great passenger airliner, no doubt, but in this role, I can't see it.
I'm talkin 747's in the 60's. His dad also flew the DC-3's to HNL after WWII which flew under the Golden Gate Bridge due to being so over gross with fuel on takeoff.