Need a good radiator source...

Well  I figured out one of my issues with my overheating '78 Midget.  The
spare stock radiator I had was 85 to 90% blocked off from corrosion.  The
three row louvered I have just isn't doing a good job.
 
Does anyone know of a shop that makes a 3 row staggered radiator with at
least 14 fins per inch, and which is no more than 1/8" thicker than the
original stock radiator?  I cannot source one locally.  
 
Thanks,
 
Michael