There's no other seme like Asami :D.
"Totally Captivated" would be my first choice.
http://www.mangago.me/read-manga/bi_no_isu/ (Yakuza)
http://www.mangago.me/read-manga/heart_strings/ (Yakuza)
http://www.mangago.me/read-manga/houkago_no_love_call/ (Yakuza)
Other powerful, strong seme types:
http://www.mangago.me/read-manga/neo_arcadia_yami_ni_saku_niji/
http://www.mangago.me/read-manga/yokubou_no_shizuku/
http://www.mangago.me/read-manga/jigoku_meguri/
http://www.mangago.me/read-manga/black_sun/
You can also go through my "Hot seme" list http://www.mangago.me/home/mangalist/37883/ although I chose them just because of their looks, so they are not always powerful.
You may also be interested in my other list with Yakuza/mafia yaoi http://www.mangago.me/home/mangalist/34881/
There is definitely no other seme like Asami :3
Yeah Asami is the best
Can you recommend some BL mangas where in the Seme is a Mafia Boss or something powerful like "You're My Loveprize In Viewfinder" by Ayano sensei I wanna read Something like that ლ(´ڡ`ლ)(づ￣ ³￣)づ