New Mac OS 10.X drivers for the Epson 3800 and 3880 Stylus Pro printers were released in late 2011. These updates don't appear to have been reported yet on NSN.
The new drivers are both labeled v8.64, but the download files are different:
EPSON 3800:
Printer Driver v8.64:
http://www.epson.com/cgi-bin/Store/supp ... =Macintosh
Mac OS X (v10.7 - v10.7.x), Mac OS X (v10.6), Mac OS X (v10.5.
epson14374.dmg - 34.4MB - posted on 10/10/11
EPSON 3880:
Printer Driver v8.64:
http://www.epson.com/cgi-bin/Store/supp ... =Macintosh
Mac OS X (v10.7 - v10.7.x), Mac OS X (v10.6), Mac OS X (v10.5.
epson14359.dmg - 34.8MB - posted on 09/16/11
New drivers (v8.64 and v8.66, replacing v6.11) are available for the 4800 series printers as well. See the Epson support site for details.