Preferably without caffeine.....a joke.

I have a small carry on container for travel. Been looking for several hours and the best I could find is a Verbatim retract mouse. Its a hair over 25mm in height, which is acceptable.

Anyone know of anything else? Some wireless mice have a wired option via usb. As long as it is no higher than 27mm, that is also acceptable. I have a trackpad and it is a terrible experience.

A wired mouse, no higher than 1 inch. Anything higher, That can be sanded down may work too. If it has a back button, that would be great.

edit: typo

Only model that I can come up to is an Apple magic mouse, but obviously it's far off the requirements :/

Corsair Ironclaw
13 x 8 x 4.5 cm; 130 Grams, 10 buttions
both wired and wireless which works right out of the packet {adaptor included} but if you want the software download it to change what they do

How flat?

I have an Adept to replace an Expert that'd gotten a bit daffy with age, but you didn't exactly specify your featureset. For example, would this 3D printed trackpad work?

Microsoft Surface Arc Mouse is very flat (just ~ 14mm when packed), but not sure if it is good for gaming,

How flat?

25mm/1inch

Otherwise it would require sanding down.

The microsoft flat mice tend to die super easy. Plus some genius thinks, putting a mouse in sleep mode is a good idea on many wireless mice. Like having an umbrella made out of sugar.

I really would appreciate a mouse that flat, but wired ones last longer than wireless.

edit for typo.