where did you get them?
I buy them direct from China. I have some contacts through eBay, referals and often people contact me directly. Usually you can email some of the eBay folks and inquire about larger orders. You usually need to request at least ten times their biggest listing on eBay to get their attention and have them sell off eBay.
The MakerSlide hold only affects new fabrication. That means milling, routing, cutting. Anything I have in stock like motors, pulley,belts I can ship. I can ship the Y upgrade. Email directly if you want one.