The last on I know about is the Botanical Garden House. I think I bought it in the Crown Shop.
Sydney Skyblood lvl 104 Fire
Huses like you wrote are available only in exceptional situations? Events, sell out or so? I can see in the Crowns show only the classic houses (Like Red Barn Farm what i own, or the ones named by schools and so..)
I do not know if this has changed but the only house that doesn't require crowns or a bundle is crafting the Celestial Observatory. It is a lot easier to craft now due to the increase in certain reagent drops on later worlds (so more of it selling in the bazaar) but it is quite a bit of work to do so
I think you may have miss read the page, it sets your crafting slot on a 12 hour cooldown(when you craft it) but the house is very much permanent. It is kind of a slog to craft and once you have the reagents you need to go to the ice forge in Grizzlehiem (not a crafting table
There are only 2 ways to get a house with a dueling circle and all houses (and any dueling circles in them) are permanent. The only way a house goes away is if you choose to sell it.
The first way and what's most commonly done is to buy a bundle either from a store that sells them (such as gamestop) or online from wizard101 (if you go to buy crowns and scroll down the bundles available are at the bottom of the page. But be careful not all bundles come with a house, some come with other things like gauntlets instead.
The second way is to craft the celestial observatory, which I believe is the only craftable house that has a dueling circle (I could be wrong on this since houses have been added since I last looked at crafting one but pretty sure this is still true).
The botanical gardens someone mentioned earlier is a bundle that was once sold in store and then moved to being available online at wizard101. It's no longer available online so you can't buy it now unless there is a throwback thursday or you get it for about 10$ more than it cost in store from websites like amazon.
Going back to the observatory thought the 12 hours thing is the cooldown on the timer as the others here have said. A house and the dueling circle in it is always permanent and won't ever leave your inventory unless you decide to sell it or something glitchy happens.
Personally I recommend the newest empyrea bundle if you choose to go that route. The village is awesome and pvp circle entrance is behind a waterfall and looks really cool.
If you decide to craft the observatory know that reagents aren't hard to get now but you will end up crafting a bunch of furniture like teleporters from other recipes in order to get what you need for the house recipe. Even with more reagents available it will probably take a decent amount of time to craft the house due to the amount of reagents for the multiple recipes needed.