using only a pic would be very difficult, the amount of data that has to be sent to a LCD without a controller on it is imeanse, just flick through the data sheet for one of the LCDs your looking at and do the maths, even a 40Mhz PIC couldn't drive a 320*240 LCD alone.
Try using a controller like the SED1330/5/6. (i have some code that covers basic stuff, init/setup/command issuing, for the G2446 on **broken link removed** $25 its quite a bargin imo.
Once you have a controller you don't need to constantly refresh the LCD with information. So the pics (which are slow) can do simple animation and stuff.
If you realy don't want to use a controller like a 1330, then try looking at some of ARM's products, these RISCs are often upto 100mhz, and still low on battery power!