Using a 5V LCD screen from a 3.3V Raspberry Pi GPIO pin
If you only need to send data to the LCD you can use HCT buffers. HCT is TTL-compatible HCMOS, so made to work at 5V, but instead of needing 0.6 Vcc input for a high level (or even 0.7 Vcc) it can do with TTL levels, i.e. 2.4 V for a high level.  

The 74HCT241 is an octal buffer.

For status and other unidirectional lines from the LCD you can use a resistor divider to scale the 5 V down to 3.3 V. A 10 k&Omega; resistor in series with a 20 k&Omega; gives you 3.3 V out for 5 V in.