is there any manga in which the omega is the top and alpha is the bottom just curious lol...

http://www.mangago.me/read-manga/boku_no_high_spec_kareshi_sama/

I am on a hunt for these and your is still the only one I've found lol

http://www.mangago.me/read-manga/sutenaide_my_hero/

maybe this one.
i´m not sure yet.

same XD oh, I've read the one Todoroki-chan linked; it also has an omega seme. Also if it helps, http://www.mangago.me/tag/omega%20seme/

just check the tags
http://www.mangago.me/home/mangalist/290545/