Here's another keris with (m)boto rubuh blumbangan in South Sumatran fittings...
(Shallow tikel alis + sraweyan extending along the usual sogokan area in this example.)
I got some more blades in S Sumatran fittings that exhibit a slightly concave gandik.
(The blade shown is of above average length but less than 40cm from memory.)
Regards,
Kai
(pics courtesy of Ron)