If you simply cannot wait for Yamaha Corp to market things to you, here is an adaptor you can install yourself. Simply rip out the keys from an Evolution MK49 MIDI keyboard, having first secured permission from the owner, bend the key stoppers down and screw this adaptor in its place. You will need four copies of the model shown plus one for the top C. Take the STL files I will provide to your local prototyping shop and make sure they have a tough photopolymer in their machines. Choose two colours which you think you can live with and hey presto. To receive a CD containing the files and further instructions send me an email. I am planning to make adaptors for other keyboards, depending on demand. (Think about those small Yamaha keyboards like the DX100 etc)