3DVerkstan's (http://3dverkstan.se) first tests show that it is possible to print at at least 16mm3/s with great results, the blue vase pictured is a single wall print with 0.5mm layer height, printed at 40mm/s (16mm^3/s)

Forum Thread: http://umforum.ultimaker.com/index.php?/topic/6548-how-to-modify-machine-a-um2-nozzle-to-08mm/

The process is relatively simple if you got the right tools at hand, in my case i have the tools i need at Stockholm Makerspace (www.makerspace.se) the process i used is as follows:

1.) Clamp the 6mm front part of the nozzle assembly in a 6mm collet mounted in a collet chuck fitted to the lathe head stock and make sure it runs true, also make sure that the flat part of the assembly is perfectly flat against the collet front.

2.) Mount a ER collet chuck with a 1/8" collet in the lathe tail stock, and set up a 0.8mm carbide milling cutter to drill the hole and position the head stock so the tool is just outside the nozzle assembly in the retracted position.

3.) Run your lathe at highest possible speed (for me it was 2200rpm), since these small carbide cutters love the high RPMs and will be prone to break easy if you run them at lower speeds, then use the hand wheel at the tailstock to drill out the nozzle orifice to 0.8mm.

4.) Put up a piece of aluminium larger than 10mm in the collet chuck, turn the face flat and then drill a 5mm hole and tap it with a M6*0.75mm tap to be able to screw in the back of the nozzle assembly.

5.) Screw the nozzle assembly tight in the tapped hole, put up the 2mm end mill in the tailstock, measure the front of the nozzle and zero out the tail stock dial, fire up the lathe at maximum rpm and use the tail stock to mill down the front of the nozzle about 0.3mm.

Step 4 and 5 is theoretical since i did not have a M6*0.75 tap handy but had a milling machine and therefore used the milling head and a milling vice to do the job, but the way i describe you could do it all in the lathe and it would be very repeatable :)