Adding a tank to a plain round tube bike

[baldwooky]

Heya, so I got a project, technically 2, identical bike frames I'm in the process of building up.
The bikes in question are just plain old round tube bikes that did not have tanks on them. I would like to add tanks to them to give them that "rat rod" motorcycle type look, but I cannot find any tank that look like they would work, most of them are meant to fit inbetween 2 bars. I figure a plain old tank with a standard round tube attachment would be fairly common, but I guess its not.

Can anyone point me in a direction for something like this, or am I going to be looking for a long time on something that will most likely be very pricey? Repros are fine, and cheap is even better, anyone ?

 

[ifitsfreeitsforme]

is welding in another tube out of the question?

here's bikes with tanks hanging from top tube(s)

 

[baldwooky]

Welding isn't out of the question. I would prefer it to be either welded on, or have a round slot on the either side of it(preferably on the bottom) so that I can drill a hole through the frame and secure it.

I would prefer to not have to "strap" it to the tube if possible.
My main issue is finding a tank that doesn't have cutouts for tubing in it from a previous frame.

Something like the west coast chopper tank would be ideally what I'm looking for, but I ain't about to buy a complete bike for $150-200 to takeoff a tank to put on a trash find, albeit a really, really cool trash find. Even an old motorcycle gas tank should work, I'd think...

http://www.motoredbikes.com/showthread.php?13748-Jesse-James-West-Coast-Chopper-Bike-Conversion