Yeah this same things has been bugging me, I'm kinda surprised that with the rise of twins and HOM there is not more.
I have been reading Having Twins and More by Elizabeth Noble and really injuring a lot of background on twin development and history.
Do you know that according to her twins actually develop faster for there gestational age for the first part of a pregnancy, and only slip to being smaller in the last trimester? An interesting thing to understand and very different from what my un twin wise nurse told me.
I have a iPhone app that I like and am just bummed that I can't tell it that I'm having twins.