This year you've got more than 5 of them in Olympic - Rudisha, Managoi, 400m duo (kishoyan). They are continuing the legacy started by the konchellahs.
Transmara "maasai" are actually Kalenjin - mostly Sabaots. They were moved en-masse in 1930s-1950s by British from Eldoret & sorrounding regions and nearly all have living relatives among Kalenjin.
Only original maasai who lived in Transmara are Siria maasai [ole Tunai clan] - the rest are Kalenjin masquerading as Maasai.