I've got an older 2.0 GHz Core Duo white MacBook 13" w/SuperDrive that runs great and is in pretty good condition. And I'm willing to throw in an iPad, brand new.
What I want, is a new or newish Unibody MacBook 13". Depending on your trade offer, that's which iPad I'll throw in. (basically, got a bunch of Apple Store credit)
BRAND NEW Current Gen Unibody 13" MacBook = MB + iPad 32GB WiFi
NEWISH Last Gen Unibody 13" MacBook = MB + iPad 16GB WiFi
Other options and considerations will be negotiable...