I've made a prototype “L” bracket for the K-1, that can be used with or without the battery grip to suit Manfrotto RC2 tripod heads.
I use Manfrotto heads and the Spider Pro holster system on a Think Tank Pro Speed belt, hence the ball pin.
My intention was to keep it simple for my own use, with this in mind, it is not possible to access the output ports on the left of the body or change the battery while the bracket is attached. When I shoot professionally I have never needed to change batteries mid shoot (I use 2 batteries).
If there is enough interest expressed here and elsewhere I will look at putting it into production.
I have set it up, so the lens axis maintains the same lateral centre when switching from horizontal to vertical, with or without the grip. Same goes for body to subject distance (fore and aft) if you decided to remove or add the grip.
To prevent the grip twisting there is a “u” shaped bracket that is screwed to the “L” bracket upright. Without the grip, 2 button head screws are removed from the bracket upright and screwed into the base to locate in the same holes in the body that the grip uses to locate itself.
Other than the 2 capscrews that hold the bottom RC2 plate more or less permanently, all the other screws use the 1/8” allen key that is stored securely in the front side of the bracket upright.
When the grip is not used, the ¼” screw that holds the "L" bracket to the grip is removed and screwed into the hole in the middle of the bottom RC2 plate. The “u” bracket is removed by removing the countersunk screw in the upright, the 2 button head screws are removed from the upright and screwed up through the base. The RC2 plate on the upright can be put onto the lower position to keep the same lateral axis position and reduce the overall height of the bracket. Pins in the upright prevent this plate from twisting.
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DaveR's Album: K-1 L Bracket Prototype - PentaxForums.com