So i just recently discovered the manga for tsukihime on . It's not posted to completions yet but there is quite a bit there and also it follows arcuied's route. After reading what's been posted so far [up to vol6. chp. 48] i was surprised. There were actually a lot of scenes in the mange that weren't in the anime or visual novel.
There are more flash backs of scenes of the real SHIKI and shiki talking. It shows shiki going into nanaya mode quite and bit more than the anime or v/n. Also, there are some fight scenes that i've never seen before in the anime or v/n such as akiha fighting ciel after she discovers her snooping in the makihisa's room. In the manga, it seems that SHIKI has another power other than just invincibility and the blood thing.
I can't believe that i still find it so interesting even after playing the v/n and watching the anime. Guess that just shows how good of a story it is. And i gotta say the artwork is drawn really well to.