On a similar theme, last week's fettle was a bracket to make use of:
a) the gap under the seat afforded by the 'seat brackets for shorter riders'
b) two braze-ons on the, erm, 'seat tube', intended for a bottle cage adaptor designed for use with the mesh seat, which in my case I have not got.
Why pay HPVelotechnik prices when you can get a bit of aluminimum U-channel and fill it with drillium
[1]?
Reasonably pleased with the result, shitty paint job notwithstanding. (An open tin of Hammerite Ultima being available and less of a pain than spray paint.)
The space between seat brackets is just enough for the Gorilla Cage, which means you can't slide it off the mounting cleats without either unbolting the bracket or removing the seat, unfortunately. It's a decent place to keep a jacket, as it's out of the splatter zone
[2] and easy to get at even with panniers attached.
The water bottle isn't really accessible while riding (the adaptor mentioned above mounts them upside down and splayed outwards), but I don't care as there's a more accessible one on the derailleur post, and my preferred solution for touring is a water bag on the rear rack with the hydration hose. (That modified bottle mostly gets used on the Red Baron - I was trying it here to see if it would work.) This is a bit more aero, anyway.
[1] My cheap Chinese hole saw wasn't really up to the job of whatever alloy this is, but I'd started so I finished.
[2] On the previous bike I'd strap it under the frame between the fork and the lowrider rack, but the new geometry doesn't lend itself to that.