There really almost was an Xbox 1.5
Hiroshige Goto of japanese mag PC Watch, found out that Microsoft had actually planned on making and releasing an Xbox 1.5 before their next-gen machine. The Xbox 1.5 was basically supposed to be a souped up Xbox (better cpu and/or gpu) that played all of your Xbox games, as well as the shiny-er Xbox 1.5 titles. I'm thinking they scratched this idea because it wouldn't have much time to become too popular with the Revolution and PS3 due to come out this year. Interesting info none the less.