I realized some of my friends across a few oceans missed out, due to the day-night time difference, hence I will open this up for a limited numbers more. Also doing this so that the acrylic sheet is better accommodated.
Good news is, thanks to this awesome community, who are willing to throw money at a noob like me, the numbers were great so far, thus the prototype will now use the exact same dimensions as the final planned keycap, not just 4mm. And if for the final numbers are good, we could have colored top layers as well!!! Yipee!
Exact number of open slots will be declared soon enough. Get your ideas ready!