A short update: the project is not dead but a bit down on my todo list which hopefully is getting shorter by the day.
I am currently making a mini CNC mill that I am going to use for drilling and milling PCBs++, it can bee seen as a companion to the exposer. It is my intention to add an ATC to that (it is the aluminium structure in the table), I am lazy and do not want to change bits myself. The mill will run my ARM port of grbl which by now is quite a bit changed from the original, amongst the numerous changes are canned cycle support, a new state machine - and I am working on spindle sync for my newly aquired mini lathe.
I may start a new project here for that later, especially if I get the ATC to work.
A prototype for the exposer is fairly complete in the mechanical department, I have to finish the laser carrier design (only needs dimensional verification) and 3D-print it - then it will be time for the electronics and firmware changes. It is my intention to make two version of the electronics, one for TIs MSP430G2553 launcpad and one for a custom board with MSP430FF5310 as the MCU.