Here are some interesting ideas that have been sent in by Doug Best...
"Just as the iPod lineup developed and branched out, so does Apple have plans for the iPhone lineup. Here's some of what is being considered:
"A "Pro" or "Max" model, that is noticeably thicker than current model (over 15mm, versus 11.6mm for existing iPhone), to incorporate a battery with almost triple the duration of the existing iPhone. This model is also the 3G model. It is targeted for power users and enterprise, meaning people who may use their phone 2-3 days in a row (on a business trip) without accessing a PC or having the time or opportunity to charge it.
"Existing iPhone stays the same, along with no 3G, just Edge.
"Also being considered, and with engineering and development basically done, is a new entry model, that is slimmer than the iPod Touch (an amazing 6.2mm versus iPod Touch's already amazing 8mm), and slightly less wide (58.6mm versus 61.8mm for iPod Touch). Screen size is the same; this width reduction comes from the casing. It does not offer video playback and has only 4GB. Could be as low as $159. Name to be determined, internally referred to as iPhone Shuffle, definitely not the final name. Edge, of course."