While I don't "fish for both with the same setup" ... I do catch both with them. Largemouth up to around 6lbs, & Smallmouth around 4lbs have all fallen to my UL's and lite action rods. That was when using 4lb test mono, for the most part, and 6lb copoly line in recent years. The two biggest reasons I landed these fish are : playing the fish down & knowing how to "backwind" a spinning reel.
Now, you do have to take into consideration that I was specifically Crappie fishing at those times, and the Bass were just byproducts. I was casting jigs, jig/minnow, or marabou Roadrunners in all but a few instances. All I'm saying is that it "can" be done. I'm not saying that there's any particular brand of rod that would likely be considered as "dual purpose" when talking about Bass & Crappie.
If your lake doesn't have Slab Crappie & Hawg Bass (over 2lbs & over 4lbs respectively) ... then you should be able to successfully use a lot of different brands of rods in the "lite to med" power range ... and lines in the 6-8lb test range. A good long handled net wouldn't hurt, either
How you plan on fishing for these two species may also factor in to what length, power, action the rod has.
I do have one outfit that I "could" use for both ... but it has a specific function and therefore not often used as my primary outfit. It's a 7' Bionic Blade rod, and a Shimano Spirex 2000 reel spooled with PowerPro 10/2 hi-vis braid. It's mostly been used to cast Roadrunners & Whirly Bees around heavy cover, for the simple fact that I hate losing them .
If you don't mind the extra weight ... you may even consider some of the newer Ugly Stix rods (lite version). A good spinning reel, with a decent drag, and spooled with 6-8lb test line would make a decent "dual purpose" outfit. Or, most any quality brand med action rod and a good quality spinning reel might also work ... if the Ugly's prove to be too heavy in hand. Learning to flip the anti-reverse switch off and controlling the fish by winding the handle backwards during the fish's "runs" can make almost any outfit more compatible as a "dual purpose" outfit. You are "in essence" using the backwinding of the reel handle as a surrogate drag system.
Now ... that's all in regards to "spinning" reels. I don't currently use any of the spincast outfits that I have. But, a Z33 with some quality brand 8lb test mono, on a med action rod, should be sufficient. "Backwinding" a spincast reel "can" be done, but it's a little more cumbersome than when using a spinning reel. Adjusting the drag to be a little less tighter than normal might help.