At least, I don’t believe its a ‘good enough’ reason especially in a laptop, its far too much of a concession of functionality for many users.

I think design is a minor reason which they use as an innocent cover for the real reason – they want people to replace their iPods and laptops with new ones, not just buy new batteries.

The iPod business model is especially dependent on numerous factors to encourage upgrading.

Are you seriously suggesting that Apple did not have a good reason for making the iPhone battery non-user-replacement? John Gruber offers one suggestion: “But sealing the case allows Apple to design batteries in unique shapes. User accessible batteries are, in all cases I’m aware of, thicker, and the access panels are often squishy or squeaky or junky” (http://daringfireball.net/2008/06/tradeoffs).

Also, external USB battery packs make a lot more sense. They can have more capacity than the phone’s own battery, and can be used for any USB-powered device. Here’s an example of one: http://www.apc.com/resource/include/techspec_index.cfm?base_sku=UPB10