4/9 of those cars make equal to or less than a stock L67- almost half the list! Also keep in mind that Wes Blair was (fully?) sponsored by Intense Racing- and there was a good bit of money in that car, and even it makes barely more power than a basic bolt on L67 would.
To be fair, NA 3800 modding has been almost completely dead for almost 5 years, and as far as I know, no one has ever done a bored out stroker build running really high compression (the ZZP car would probably be the closest)- but I think its mostly because they're scared that they are going to be disappointed in the hp/$ ratio. Doing a hardcore stroker with custom pistons for really high compression means you'll probably end up with almsot $5k in the bottom end by the time all the machine shop work is done. Then, NA cars need a more aggressive cam to make big power which is less street friendly than a turbo or SC car. So you can easily wrap up another $1500 or more in your heads/cam/springs/chain setup. Then add another $750 or so for an HV3 and some headers, another couple hundred for a ported throttle body.
In the end- how much more power are you really going to make than the current record? I really do think with that whole mod list and some good tuning that you may be able to close in on 300 whp- but look at how much money you have dumped into it- you've got almost a $10k setup when you add some trans mods and a high stall converter to match the cam. You end up with a setup that gets crummy gas mileage, and isn't overly street friendly due to the big cam, high stall converter, and high compression requiring premium or E85 depending how high you go.
There is one reason why every single person on that NA record list has either demodded and sold their car, or went to boost (may be 1 or 2 exceptions)- that reason is, with how cheap and easy it is to do a simple top swap to bolt on a supercharger off an L67- its a bolt on, plug in deal and the hard parts can be had for $500 nowadays (obviously you still need fluids and gaskets). So for about the price of a cam/springs/timing chain set- which will only add 10-20 whp by itself, you add a quick 40 horsepower.
The other thing that did in the NA modding scene were the turbo kits- now they can be had under $3000- and can blow away even the supercharged setups with fewer mods- and not even having to touch the internals of the engine- leaving the bottom end stock reliable.