In Turkish folk music the G clarinet is very common with both the
Albert and the Oehler system which is said to have better sound and
more flexibility than the Boehm system.
Turkish clarinetists prefer the G Albert system clarinet for its warm
and mellow tone and flexibility - especially for slides and microtones.
The Turkish music theory divides the octave in 48 pithces - each whole
step is divided in 8 equal parts. People say it's easier to play
1/4notes and 1/8notes on Albert system.
One manufacturer of the G-clarinet is Amati (http://www.amati.cz).