Cross dressing? Something serious though

For BL, the entire Mayonaka Love Alliance series:
1 Pinup Boy - A bar staff wears lingerie
http://www.mangago.zone/read-manga/pinup_boy/
2 Otoshiana ni Hamerarete - A Cross-dresser Seme
http://www.mangago.zone/read-manga/otoshiana_ni_hamerarete/
3 Yoru Mo Hi Mo Akenai - Mama of the bar
http://www.mangago.zone/read-manga/yoru_mo_hi_mo_akenai/
4 Mayonaka Love Alliance - Continued story
http://www.mangago.zone/read-manga/mayonaka_love_alliance/

For straight cross-dressing
http://www.mangago.zone/read-manga/otonari_complex/
http://www.mangago.zone/read-manga/kuragehime/

Gen with a hint of shounen-ai
http://www.mangago.zone/read-manga/the_net_generation_teacher/

http://www.mangago.zone/read-manga/hatsukoi_kazuki_rai/
and if you're okay with school life shoujo then http://www.mangago.zone/read-manga/hana_kimi/ (not sure how serious you want it but hanakimi is not stupidly silly like Usotsuki Lily)

OMG, if you love watching Japanese dramas, I suggest you to watch Hana Kimi (a drama based on a cross dressing shoujo manga)!! IT'S THE MOST FUNNIEST SHIT I'VE EVER WATCHED!!
if you like humour, you're going to enjoy hana kimi. Please give it a try. thank you