http://www.mangago.me/read-manga/koi_to_wa_yobenai/
http://www.mangago.me/read-manga/under_grand_hotel/
http://www.mangago.me/read-manga/j_no_subete/
http://www.mangago.me/read-manga/endless_world/
http://www.mangago.me/read-manga/the_inheritance_of_aroma/
http://www.mangago.me/read-manga/kimi_ga_boku_no_subete/
My Top 3 Fav BL mangas are actually long ones - ZE, Love Mode, Totally Captivated. If you have already read them then you can try the long ones from here - http://www.mangago.me/home/mangalist/25771/
I think all the ones here have pretty good plot.
1. http://www.mangago.me/read-manga/ten_count/
2. http://www.mangago.me/read-manga/innocent_blue/
3. http://www.mangago.me/read-manga/sagatte_omachi_kudasai/
4. http://www.mangago.me/read-manga/hanaya_no_nikai_de/
5. http://www.mangago.me/read-manga/hero_heel/
6. http://www.mangago.me/read-manga/asterisk/
7. http://www.mangago.me/read-manga/110_ban_wa_uketsukemasen/
8. http://www.mangago.me/read-manga/adekan/
9. http://www.mangago.me/read-manga/kuroneko_kareshi_no_asobikata/
10. http://www.mangago.me/read-manga/gohou_drug/
Hope this helps to satisfy your cravings!ヾ(☆▽☆)
im in need of something to read. even if its something i have read already. so everyone please post your favorite BL's that are long and have a really good plot. doesnt matter if its shounen ai or yaoi.