No not specifically.. But I am basically certain they exist at one point or another. My question is why do you want to keep the old petcock, petcocks are kind of like pieces of candy in the dirt bike world because they are higher risk to damage just by being a small part that needs enough room for a hand to get to. Branches and tossed rocks can play the part and even removing a stubborn tank..
Point being is if you can buy any tank you will virtually always be able to get the petcock for it, I've found ones for a tank 30 some years old and they had them in stock by the thousands...
If you have a special cock you'd like to hang onto then maybe provide pictures and dimensions and I can send a crawler looking for it.
Hey Franky, I need the tank that accepts the female threaded petcock. The female threaded petcock offers reserve. I like that and the fact you can position the on, off and reserve lever in any position needed. If I were to post a pic of the cock I like to hold on to, it would be a selfy, And would be banned from the forum for pornography. LoL
The 2015 GT5 Pro racing kit I got from Kings, came with that tank and petcock. In my opinion, it is far better than the male threaded petcock, that to position the control lever where you need it, means adding more fiber washers so when tight its where you want it.
I cannot tell what thread it is, I also don't have one on hand but even if I did it isn't something that is clearly mentioned in the details of tanks being sold.
I do have a slightly odd but super effective suggestion. The threads used on tanks and petcocks can be matched up to any number of brass and copper parts at a place like Lowes, find 2 parts that fit and silver solder them together and polish off. You'll have a 100% perfect and cool looking adapter that you can be certain of the composition of. I've had to do similar to many old/antique plumbing fixtures that were to be reused for restoration.. Haven't needed to do it to a gas tank but I've always been able to locate a petcock for any tank and didn't expect to reuse an old part if I was installing something beyond stock either..
There are plenty of tanks marketed towards us, check out spookytooth or something legitimate and look for a tank you want. Or find something entirely else for something else and find a way to mount it to a bicycle.
Unfortunately you'll have to talk to the companies directly to get a vague idea of what thread they are using. You can work your way up from there... I know you can solder steel tanks together and I've unsoldered one or two as well but mostly by mistake. You should be able to find something by looking at a tank you like, then looking for reviews specifically on that one from the same place you can buy it from, look for information on those types of details and hopefully you'll get an answer.
I'm a fan of the infamous search button, when used correctly you'll be able to get down to a lot of specifics, a crawler isn't pulling a link and I don't have time to keyword a victory for you, sorry.
Oh and maybe find the source of the kings' kits, or look at them directly for larger tanks, chances are if the same manufacturer makes larger tanks then they may use the same format. Using gaskets to align a petcock is fine and so is adding another layer of thread sealant tape on ntp threads, if you have a quality part then it will last forever and not only that your petcock isn't the only one with a reserve setting, believe it or not that's a super common design of bike fuel valves, it's harder to imagine one not having one except for the most cheapest of components..
Well the builders don't have an answer for you either, find a vendor who can pick up a tank they would otherwise stuff into a box and ask them to measure the tank. Or find a vendor who knows whether their petcocks have a res position. Or find a vendor with a 3L+ tank that sells a compatible valve and examine the pictures of it to make a determination.
Or just stop worrying about a reserve on a tank with a range of like 200 miles and an engine that will go 20 miles on the gas that drips off the nozzle after fueling up my car.