Series, sagas and trilogies... and sequels too.

My favorite trilogy was the hitchhiker's guide to the galaxy--maybe the mathematician in me just got hooked on the idea of a trilogy in five--it certainly wasn't my ancient languages side anyway (though I did do Latin in high school--honest I did). But now the world's full of trilogies, series and sagas. I'm still dreaming one of my Hemlock prequels might make it into an anthology, or maybe my Hemlock trilogy, now threatening to grow into an Adamsian five, will find a publisher. D'you suppose...