A basic level shifting shield will be used for the PIC32 based boards, so the logic levels are taken care of
But PIC32 have 5v tolerant inputs right? So you shouldn't need to do any level shifting.
The glcd inputs should work fine with the 3v level outputs and the 5V tolerant PIC32 inputs
should work fine with the glcd 5v outputs.
To me that is one of the REALLY BIG deals and advantages of the PIC32 based boards over the DUE.
I don't see the value for the DUE board when compared to the PIC32 boards.
And for personal small projects I'd much rather use a PIC32MX250F128B part
than an AVR atmega328P.
BTW, I sent you detailed PM about GLCD support happenings and chipkit support.