Why is everyone posting their priorities to the list?  Anyway, here's mine:
    Tendou 2/3: Definitely more parts.  After the Azusa story comes Kodachi,
then Shampoo.  I'm considering having one or more of them fall for the 'wrong'
people (Kodachi falling for Ukyou is especially tempting, since it gives the
flip side of the normal-continuity version where Kunou likes Akane and Kodachi
likes Ranma.)
    Sailor Moon Future: I'm pretty slow at this, and nobody _ever_ comments.
    Ranma/Futaba crossovers: This is sort of an ongoing series, not a multipart
story.  The chief factor holding this up is the lack of ideas other than "main
characters meet and discuss sex-change and fiancee trouble".
Basically in that order.