We've spoken quite a bit before about the potential that Apple might one day "split the platform" with either an iPhone nano (very unlikely) or an iPhone HD (which we've been discussing quite a bit lately).

Right now, all existing iPhones and iPod touches sport 320x480 screens at 163dpi. The iPod nano, by contrast, was already at 202dpi during the previous, "fatty" generation. The BlackBerry Bold is at something around 217dpi. HTC is making 480x800 displays now like they're going out of style.

At some point, the iPhone will jump to HD (by which we mean 480p, or 480x800) and current generation iPhone apps, and their associated bitmap interface elements just won't look so good.

Cocoia, renowned icon and interface designer Sabastiaan de With's blog, has an excellent post up today about that very issue. He says:

Applications will have to ‘deal’ with two different resolutions at the least; icons and other bitmap graphics will have to be redesigned for the higher pixel density screens. There will, no doubt, be applications that are not ready and look very bad on the new device, or perfectly good applications are not approved into the App Store because they are not ready yet.

We may keep pushing the date forward like a hot potato, but at some point Apple and developers will have to face up to the fact that there will be a lot of redesigning, re-thinking and adaptation required. Until that day, enjoy the simplicity of developing and designing for a simple, defined hardware specification. But don’t say I didn’t warn you when technology comes and slaps you in the face.

Apple has enjoyed huge success from the relatively unified hardware model as well, so here's hoping they help developers not only prepare for, but transition to future resolutions as painlessly for them -- and us -- as possible. Any developers out there already pondering this?