If it's an LCD that just needs the negative supply for the contrast pin, then you should also be able to use a cheap ICL7660 chip. Easy to work with and inexpensive, but limited to very, very small amounts of current. (Many 3.3V 1602 LCDs, as well as some large or extended-temperature versions, even at 5V, use an ICL7660 precisely to create the LCD contrast voltage.)
Edit: heh, great minds think alike, artag!