I like the 1st one you mentioned ACEarcher, I own a St. Croix Triumph 5-foot ultra-lite, the feel on that rod is unbelievable, I use it early season for trout. You can feel the slightest nibble, it's also a great rod for tossing spinners, for me Rooster Tails are the go to, in black, brown, green and as ACEarcher mentioned a variety
of other colors just to give them something different.
My current LITE reel is a Shimano AXUL, I think that's the model, it is the lightest reel I've ever owned, it performs well and costs less than $20 most places. They used to make one completely out of plastic and it did weigh less than this current model I have, I am into LIGHT LIGHT LIGHT and this reel is just the ticket, well by far you can spend more but I take this reel out every time.
You might find a niche in selling ultra-lite gear for back packers and even fly guys that want to pack a spinning rod in their vest for those windy days or to try and catch trout while back packing. There are several varieties of pack rods out there. I am primarily a fly guy excluding very early season, however I still keep a telescopic 4 1/2 foot spinning rod and the Shimano UL in my vest, I also have a 6-piece 5/6 weight fly rod that works as a pack rod.
When you're back packing UL is just the ticket.
While we're on the discussion I'm remembering a very special rod that I had for nearly 20 years. A Kunan 5-foot ultra-lite. Kunan has since gone out of business, but that rod even surpassed the St. Croix, not for feel but lightness, there was something special about that rod, with it's spongy grip, not cork, it was quite the rod, I was showing off it's feel and bending it a couple years ago and to my horror it snapped on me, probably old age which I guess gets us all, wish I could get another.
Besides the pack rods I think the general consensus is for 1 piece rods, you can never get the feel with a 2 piece rod like you can with a one piece. Just to respond to HuntPhillipsburg's post, I bought a Quantum at a camp store once while camping in Promised Land, I love that rod, I've used it for smallmouth in the Susquehanna tossing spinners and it's fantastic, only 4 1/2 feet long but it can bring those smallies in before they are all kicked out, and what a blast.
Good luck with your store, you might also consider adding back packing products such as ultra-lite stoves, I own an Optimus Crux that weighs practically nothing, it can boil water in seconds and you can cook right on it, the smaller size propane/butane mix cans take up little room as well.
You can also consider stocking some 2,3 & 4 weight fly outfits, some are very pricey, if you're shopping for a 2 or 3 weight fly rod the selection seems very limited.
Ultra-Light all the way, that's what I say, lol, who wants to carry heavy stuff around.