Is there any Yaoi manga where The Uke is a Yandere? Not a mild one but a I'll lock you up ...

I can only think of this one:
http://www.mangago.zone/read-manga/sweet_heart_trigger/

I never got the meaning of the word yandere, but if you mean in the sociopathic spectrum and/or borderline, here are some :
http://www.mangago.zone/read-manga/love_mission/ oneshot ch.5
http://www.mangago.zone/read-manga/kusatta_rasen/
http://www.mangago.zone/read-manga/ibitsu_no_kakera/
http://www.mangago.zone/read-manga/shingeki_no_kyojin_dj_kare_no_te_no_uchi/
http://www.mangago.zone/read-manga/ren_ai_koufukuron/

Whoops I forgot these ones !
http://www.mangago.zone/read-manga/hetalia_dj_bathroom_rhapsody/
http://www.mangago.zone/read-manga/tonari_ni_sunderu_neko_no_koto/


http://www.mangago.zone/read-manga/high_school_lullaby/
* Related chapters :
http://www.mangago.zone/read-manga/sakasa_moji_nara_suki_da_to_ieru/bt/c001.7/
http://www.mangago.zone/read-manga/shoujo_c/