rusty fuel tank...What to do?

["stephen@domain.elided" <stephen@domain.elided>]

First I'd like to thank everyone who offered advice on *'71 Snag without 
power*.
All but one suggestion was implemented but with no success on restoring 
the lost power.

The actual problem _seems_ to be a rusty fuel tank. 
Why didn't I notice the dirty filters? 
Why did this not turn up when the fuel line pressure was checked?

-Before the loss of power developed I had replaced the in-line fuel 
filters. The new filters had less than 200 miles on them...I had (false) 
confidence that they were clean. 
-When the problem developed I checked the filters and the fuel-line 
output just prior to the carbs. All OK.
-What I didn't check was fuel poured _out_ from the "IN" side of the 
filters. When I did check this what came out looked like that 
radiator-stop-leak product with all the copper flakes floating in it.

My theory...
The fuel flow was checked when the engine was cold. As the engine ran 
rust particles would block the filter medium and fuel flow. When the car 
sat overnight for example, the rust would settle in the filters 
(partially) clearing the filter medium for the next go 'round. Repeat ad 
nauseum.

I pulled the fuel tank and removed the (fuel-level) sending unit. After 
siphoning off six gallons of gasoline and draining the rest from below I 
found the inside surface of the tank to be rusted evenly. 

What next? 
I dropped the tank at a radiator shop for cleaning. The shop owner 
suggested cleaning and a plastic coating for the inside of the tank. [One 
week and $80 for the cleaning and coating.] When pressed he couldn't say 
exactly what type of plastic it was by that it might be like epoxy and 
would look like rust in the tank! He did know of a tank treated ten years 
ago that was still in full service. Only ten years? He said it was the 
most amazing thing he'd ever seen. I'm intrigued. I asked if I could 
watch but was bombed with little excuses concerning timing, fumes, and 
liability. 
Am I buying the king's new clothes?
Does anyone have experience with this?
Suggestions...

If everyone has had this experience and it's considered common knowledge 
I will pay penalty for posting this frequently asked question by 
assembling a Stag-FAQ. (I read once that no Stag-FAQ existed.)