Lots of good info thus far, but here's how I'd sort it.
Alpine Trekkers (also called Tour Wreckers or Day Wreckers) would be an option for you if you're going to be skinning on fairly mellow terrain and not skinning for more than an hour or so each way. No gnarly climbs, no bad sidehilling, no full day tours, and you'd be fine with a pair of Trekkers mounted into your downhill binders. Mostly, this would allow you to tour some but have the solidity of downhill bindings for jibbing and stuff.
Fritschis aren't a horrible option, but I've seen enough dudes accidentally go into tele mode to scare me off them. All the plastic in the heel lock seems doomed for people jumping off stuff.
The Alltimes are heavy, and don't solve the issue of a jibbable touring binding, they just work around it. Next.
Guardians/Trackers seem like a really good option. They've gotten good press, a hell of a long time in development, all metal heel connections from ski upwards, and no click out to switch modes. My only caution would be that they are new on the consumer market, and new technologies aren't always what they're cracked up to be( Line Reactor bindings, anyone?). The Duke has changed significantly in a few years; often times a product gets a few fixes after its first consumer season. So buy into the hype with caution. That said, they're probably my favorite option for jibbing on a touring binding. Hope for good things.
The Tyrolia Adrenalins seem interesting, but they've got plastic in the heel connection, so I'm really leery. And again, this is their first consumer season. But maybe they're great. No experience yet.
Dukes. Oh Dukes. Mine are from the first year, and they're incredibly loose and wobbly. They've been beaten to hell and back several times, so I don't blame Marker. I've had the climbing risers pop out on steep switchbacks. I've double ejected several times when it was unwarranted; I'd totally echo the sentiment that Marker's touring bindings don't release consistently at DIN. They ice up in touring mode and the plastic on plastic in the heel is terrifying for switch landings. All that said, the newer ones have fixed a lot of the issues, and offer the widest platform of anything (because they use the connecting bar base to contact the ski topsheet, thus making it even wider). I'd probably buy another pair if I was looking to do minimal longer touring days on a ski that I also wanted to charge inbounds, albeit only forward.
Dynafit/Plum/G3: Tech Bindings.
If you're going to jib, these aren't for you. But if you're looking to tour or do ski mountainerding, they're the best options going. They require special plates/grooves in your boots to work properly, the toe connection is both binding and touring pivot, and they don't transmit power as well as a race clamp might, but they're light and generally dependable if you're careful, not jibbing, and not sending huge cliffs. I'm headed this direction this year for long tours, and can't wait to drop 10+ lbs off my setup weight. (Probably will be 186 Vicik + BD Quadrants + Radical FT 12s).
Your boots are also something to think about. You mentioned that you'll be rocking SPKs, so know that they've got no touring mode and will keep your ankle locked the whole time. You can tour like this, but it's not nearly as comfortable as something with a walk mode.
This is all personal opinion. Good luck with touring; the first time you skin up something you used to bootpack or struggle along your life will change forever. Amazing feeling.
