It never rains, but it pours. Yesterday Samsung posted the Android 4.1 Jelly Bean source code for both new Galaxy Tab models and the AT&T Galaxy Note II. Today they're keeping the open source train rolling with the first available code for the new Galaxy S III Mini, the flagship model's 4-inch brother-from-another-mother. The 4.1 code is available now from Samsung's developer website.
If you're wondering why the GSIII Mini needs separate code from the standard Galaxy S III, remember that it's actually quite a different beast under the hood. Aside from the 4-inch 800x480 screen and other mid-range specs, it's running a 1Ghz dual-core STE U8420 processor, with completely different architecture from the Exynos chip in the international model and the Snapdragon powering the LTE version. In any case, modders and ROM developers now have all the tools they need to tweak the stock firmware or create entirely new ROMs... hopefully with some 4.2 goodness coming down the AOSP pipeline in a week or two.