For what it's worth, I regularly use a USB card reader and copy
large files regularly with absolutely no problems.  This is on
NetBSD/i386 3.1 and -current.

Brian.

-- 
  Brian de Alwis | Software Practices Lab | UBC | http://www.cs.ubc.ca/~bsd/
      "Amusement to an observing mind is study." - Benjamin Disraeli