i'd like to see software + hardware (a double ipod ended cable) that would let you plug your ipod into your iphone and you could play music and especially video from your ipod on your iphone (and its beautiful screen).
I remember when Apple first released the USB camera adaptor thing for the iPod and thought w/ the right hack, you can connect another ipod to it w/ its cable and do that. http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore.woa/wa/RSLID?mco=20538A8A&nplm=M9861G/B