Small update:
New miners are almost ready, I'm working on the prototype and I'm ready to assemble the new units in 10 - 20 days.
Meanwhile someone contacted me on Bitmessage, proposing to advertise/bootstrap his service and receive in change 10% of their revenues (I would distribute this income exactly like if it has been mined), it may be an help to speed things up. I am evaluating if it's reliable and whether it's the case or not to accept his proposal since he is anonymous...