I don't think the pattern is out of date but there are fewer options and makers of slipjoints in general compared to the old days.
I buy all my trads previously owned. I picked up these that seem to satisfy what your interest is. The Barlow is one that I was not liking initially till I handled one. Its a great pattern with a few flavors to choose from, large blade wise. My Pemberton continues to dominate pocket time tho.
One of my favorite jack patterns is the Camillus 23. Too big for me to carry (says the dumbsmurf city I live in), but it meets the OP's requirements. They can get pretty pricey, though. I can't remember what pattern number Camillus assigned to the smaller equal end jack.
The Camillus 52 is a nice mid sized EE Jack if you can find one. They were only made for a short period of time.
What years did they make it ?
What's the pattern number on that jack?
Knife market is a though business, with quality increasing and prices dropping.
I've not seen a lot of that. Granted, there aren't many brands that I actively follow, but one in particular (Victorinox) has made some pretty substantial price increases over the past six months or so. Case seems to be holding more or less steady.