Campi, Miche, JoyTech and probably a few others use 10mm x 26 threads per inch for rear axles. I'm pretty sure the root angle is 55 degrees too. Wheels Manufacturing makes a wide variety of 26tpi axles.

Everyone else uses 10mm dia. x 1mm pitch w/60 degree root angle.

Campi dropouts and rear derailleur fixing bolts are also 26tpi but there are so few threads involved, and dropouts are so soft (compared to cones) that you can mix and match.