Yondaime Ooyamato Tatsuyuki (the whole series ), Bi no Isu, Links...my ongoing list. Let me know how you like it. http://www.mangago.me/home/mangalist/347760/
If u don't mind a more comedic approach, try honto yajuu
Well, if you're looking for something equally as complex in terms of plot, if not more, I'd recommend Acid Town:
http://www.mangago.me/read-manga/acid_town/
It truly is a masterpiece, but the focus is more on the drama, so you might be slightly disappointed if you're looking for romance.
Hi i was wondering if anyone knew any good yakuza yaoi besides Saezuru Tori wa Habatakanai? Thanks in advanced! (づ￣ ³￣)づ