Possibly interesting idea.
Capture the Flag chess

That sounds like it will be similar to racing kings.
I would like to disagree with that, mainly because this is kinda a very different concept from King of The Hill. As in, this is like a 'reverse KOTH', where if your royal lands on the hill square you lose (Which is why your opponent drags your royal there).
In Racing kings, 2 kings of their own will (wow im sounding all philosiphical and stuff) race to KoTH, and no checks are allowed.
You could even go as far as to say that this is the opposite of racing kings, because in CTF you dont want to get into the hill, while in Koth you do
Im looking to make a new variant called capture the flag
the idea is the king is replaced with a flag the other side has to take it and get to their side of the baord with it