Re: electronic goldmine ferrite rods on sale
38lbs! That's not quite UltraLight :)
You mention 2012 as the year when FSL was introduced.
Here is a design from 2006 by UA6CA, the link still works:
It is in Russian, but the pictures are informative enough. They also used it for TX on 160 and 80m, up to 10W.
73, Mike AF7KR