So- Pi Supply now have a gesture controller with an MGC3130 controller (same as the venerable SkyWriter). Only difference is that they’ve done a pHAT format one, and a larger one too.
I do wonder what these new boards might offer, over our beloved pirates wares?
Pick one up and make a comparison review ;)
There’s also Hover which, iirc, uses the same IC: http://www.hoverlabs.co/products/hover/
In terms of engineering- they’re all pretty much just the reference implementation but may differ when it comes to calibration, etc.
As @gadgetoid says these are essentially based on the reference design from the chip vendor.
As a company we’d shy away from creating a product that’s equivalent to the offering of a third party if we were aware it existed. We tend to only release something if we think it offers something new in format/functionality that warrants visiting the concept again!