Take this with a 7-to-10 inch capacitive grain of salt, but French site M4Ever [Google translate link] is claiming that we might just see iPhone 4.0 beta fairly soon (hey, maybe as soon as the Jan. 27 media event?) Macrumors supplies the clean text:

Several of our sources give us two pieces of information concerning the famous Apple tablet: In late January, in addition to its tablet, Cupertino should have a beta of iPhone OS 4, accompanied by an SDK. Our informants also tell us of a "simulator" specifically adapted for the tablet. Evidently, the major novelty of the SDK therefore concerns the interface, making it easier for developers to adapt to different screen resolutions. The new iPhone could also benefit from a higher pixel density.

Real, fake, really fake? We know we'll get iPhone 4.0 seeded to developers eventually, and resolution independence (i.e. iPhone HD and iTablet) is something TiPb's been talking about for a while now. No matter what, if Apple wants App Store level success to continue with next generation devices, they'll need to get the SDKs into the hands of developers, so while -- again -- this is just a rumor, it's going to come true sooner or later. The only real question is... when?