I was thinking burichi would be a good name since it's the roman character translation of the katakana for the title, but I'm sure it's probably taken. Unless you were to extend the vowels like it says you should then it'd be buriichii, but that looks bad.

senkaimon would be okay. It's not too confusing or hard to spell, and with it being the opening between the human world and the SS there could be some kind of symbolic nature to it.

Just as long it's not something like The Shinigami's Lounge...