No worries, it is a 100% valid and reasonable enquiry.
The reality though is "months of work for a human being" which ultimately would bring very little reward (for our business or for the majority of our users).
It is really the "system-wide integration" of a new matrix colouring method into CharPad (its whole eco-system) which is too painful.
A far simpler project however would be a separate app that takes a CharPad project as input and allows the very thing you are seeking, allowing the user to paint/colourize the colour RAM and export the (colour) data.
This could then just be dropped into your game and used, the input project might be designed in CharPad using "per map" matrix colouring to keep the charset usage to a minimum before you use the new app to colourize it.
I will have a think about that one :)
+ also please check out the existing CharPad (binary/text) export option...
'Export Colour Map (per map char cell, CmLo)'
It may be capable of providing the data you require, albeit not quite as conveniently as you desire.