How are we gonna build this? Well, we had money, we were generating money from the 2600 stuff... We thought about building a 16-bit version of the 6502 called the 6509, we specced it all out, we got people to bid on it and then we decided: we're building three custom chips - why put even more schedule risk into it? So we dropped that - but that became the 65816 which wound up in several Apple products. Nice processor.

The Atari VCS used a modified MOS 6502 CPU, and the same CPU was chosen for the Atari PCS. During the development process, Atari considered a 16-b extension of the design, tentatively called a “6509.” It would have a 16-b accumulator, two 16-b index registers, a 16-b stack pointer, and a zero page pointer. After consideration, Atari decided not to risk the development schedule any further, since it was already committed to more than one ASIC for I/O. However, the “6509” design became the “65816,” used in later Apple II-family models.

We thought about building a 16-bit version of the 6502 called the 6509, we specced it all out, we got people to bid on it ... - but that became the 65816 which wound up in several Apple products.