hi, im yap, i just bought your machine. exciting!!!
how fast the machine can delivery? 
how fine can go if i do rubber stamp can go up to 5pt?
It should start shipping sometime mid next year hopefully!
Shipping begins in December . Dan has stated he is hopeful to have all pre-sale units shipped by Aug 2016. I am hopeful that with the large amount of investment money available, production can be stepped up and units can ship sooner than expected, but that remains to be seen.
About stamps, there is said to be a rubber stamp mode for the Glowforge, and I would assume the detail could be very fine.
More info here: Rubber Stamp Mode