If you're in the market for a GH4, the YAGH interface (which adds a plethora of professional video features), and a solid kit lens, you can snag yourself the whole bundle at a discounted price on B&H right now.
The kit, which comes with the GH4 body, the YAGH interface, and the Lumix Vario 12-35mm f/2.8 kit lens, usually retails for $4700, but is currently on sale for $3900.
We all know that the GH4 offers users a tremendous value because of its ability to record 4K internally and output it externally over its HDMI port, which enables it to be used with a new generation of external 4K recorders like the Atomos Shogun. However, when paired with the YAGH interface, the GH4 gains a whole host of features (chiefly a 4K 4:2:2 10-bit output via quad link SDI and XLR inputs with full phantom power) which are usually reserved for professional video cameras that are often far more expensive.
Of course, when paired with one another, the GH4 and YAGH base become an oddly-shaped and rather bulky unit that isn't particularly ergonomic, and you lose certain features (like the ability to record internally on the camera), so it's not for everybody. However, the feature set alone of this combination speaks for itself.
So if you're currently in the market for a relatively small camera package with a large feature set, this might just be the best time to hop on board the GH4 train.