elongated

I'm in need of a 10" rough-in toilet with an elongated seat. Really hoping to find a one-piece if possible? Or at least one that has a concealed trapway. Is this possible? Am I just looking in the wrong places? Is it possible to use a slimmer tank on a different base to get the concealed...

Western Pottery B832/T8-HP Toilet Elongated bowl. Standard Height 800 Grams MaP testing. 2" trapway Western Pottery B832/T8-HP with 1.28 GPF tank

Does anybody have any experience with this Bath Royale toilet seat on Amazon? https://www.amazon.com/Bath-Royale-Elongated-Slow-Close-Quick-Release/dp/B00NAIO6CM/ref=sr_1_5?ie=UTF8&qid=1546970163&sr=8-5&keywords=plastic+slow+close+elongated+seat It is basically the top rated one on there with...

The Gerber Maxwell WS-20-912 toilet with pictures. It looks to have a 3" flush valve and a trapway that around 2". I found this in a new home provided as their builder grade toilet. WS-20-912 Here is the standard 12" rough. I haven't seen this fill valve before, and the flapper is...