For steel full rigid, I reckon it's actually getting harder and harder to find for reasonable money. AL frames with also the ubiquitous knackered crap suspension forks goes straight to the tip with no hesitation for me. They are worth about as much as the derailleur hanger.
Really got to spend time on Gumtree or the local ads and hope something turns up that wasn't too trashed and molested over the years and the seller doesn't really know what they are selling.
I love these kind of bikes, and with some research and patience you really don't need to go bottom of the barrel. Plenty of obscure brands did similar, and often with a few touches that made a quality difference.
Sometimes wide search terms like Shimano XT, LX or STX throw up some pearls amongst the stones.