It's not quite as nice as it could be. Apparently the "24" in PIC24 refers to the instruction width, so 128kbyte is only 43k instructions (still, a 32kbyte arduino is only 16k instructions...)
I didn't necessarily intend that this be from "someone" who wanted to compete with the official Arudino team. In theory, the team could do a PIC-based board as a followon themselves. (I don't see any other alternatives for more than 32k of program space in a DIP socket. It depends on how important you consider that feature compared to the architecture...)
Staying in the Atmel AVR's you have ATmega 164p, 324p, 644p, and 1284p, all of then are 40 pin DIPs, ranging from 16K of flash up to 128K of flash, the 644 is a very nice chip offering 4k of SRAM and its relatively cheap.
For the banked ram in PIC's, well you programm in C, so you dont need to care about that and they already have gcc compiler for almost all their ranges, so making a fully open-source compiler for pics is much easier than say at 4-5 years ago.