Sure. You can see what my intention was before I asked Santa for one for Xmas.
@marcparnes kindly gave me the dimensions.
Link here
https://www.zumouserforums.co.uk/viewto ... 639#p23639
It turned out very similar to that balsa wood mockup.
For those who do not know what we are talking about, the Honda ST1300 does not have the traditional handle bar 'pipe' across the steering head. It has two cast alloy arms that are bolted securely to the yolk that fits across the top of the fork legs. The round diameter handlebar is taken up by the grip, and the brake and clutch lever. That's it. No place to bolt anything.
Requirements: One of each of these.

- Hbar controller 0.jpg (69.65 KiB) Viewed 1288 times
The Ball end on the left is supplied with every Zumo Stanav that I have owned. It is a "RAM Handlebar Base", apparently". This fits over the existing brake lever half moon clamps. It requires two longer bolts. The curved recess is there to accomodate the curve of the loose half of the existing clamp, it does not replace it. This gives a spare RAM ball in a very handy position.
The joining RAM ball clamp is also supplied as standard. I had a longer one - which is much better, so I used that.
I had another 'RAM Handlebar base', but for the XT2 controller, I needed something round to clamp onto. That's where the short length of white water pipe comes in. It it is just too small to slip over the square section of the mount. Which makes it ideal. So I shortened the RAM mount with a hacksaw, held the water pipe over a hot flame - close enought o make the plastic flexible, but not close enough to melt it, and shoved the soft platic over the square end of the sawn off mount. A bit of insulation tape, and I filled the gap with epoxy resin and let it set.
A bit of black gutter sealant at each end and some black insulation tape to make it look - well, black really. And we have the following

- Hbar controller 1.jpg (171.53 KiB) Viewed 1288 times

- Hbar controller 2.jpg (129.14 KiB) Viewed 1288 times

- Hbar controller 3.jpg (149.3 KiB) Viewed 1288 times

- Hbar controller 4.jpg (127.38 KiB) Viewed 1288 times
The cable ties are a safeguard to stop the clamp from slackening. I want to fit an ordinary nyloc nut on there, but I have yet to find one with the correct thread pitch.
The position with a gloved hand is ideal. I have large hands - about 4XL glove size - and the only thing that is slightly awkward to get to is the red 4-way flasher which is normally operated with the thumb. But index finger can access it easily.
Wiring was not difficult - but it proved impossible to get it so that I could detach the screw joining piece. MY XT2 is mounted on the left hand side of the shelf behind the windscreen, so the cable has to come from there. The cables are joined somewhere in the space behind the mirror mount.
The length of plastic pipe could have been shorter. I will cut it off eventually, but it is not in the way. I wanted to make sure that I had enough adjustment available to get it in the right position first - easy to access; doesn't interfere with access to other controls; easy to get hand off and on the grip; doesn't block visibility in mirror; doesn't affect right steering lock (collision with screen).
I can reach the bottom two buttons easily with my thumb without my hand leaving the bars. The top two are accessed with a small lift of the hand from the bar.
The controller could go a bit lower and further left - which would be better for reach - but one thing that I hadn't considered was the view of the rear view mirror. That view is affected by how tall you are.