the pricing should only be another $10 or so above the price of the controller itself

The MENSCH™ microcomputer W65C265QBX is a small single board computer (SBC), 1.25” x 2.25”, using the System on a Chip (SoC) W65C265S MCU. The W65C265S was invented and designed by Bill Mensch WDC’s founder after he invented and designed the 65816 microprocessor. As a recognized pioneer of the microprocessor industry. Mr. Mensch’s twenty two patented inventions were/are used on the original Motorola 6800 Microprocessor Family, MOS Technology 6502 Microprocessor Family, and WDC’s 65C02 and 65816 Microprocessor Families. As an electrical engineer, 1971 BSEE from The University of Arizona (UA), having taught graduate level classes at Arizona State University (ASU) on SOC design for five years, advisor to four university colleges of engineering for over two decades, the MENSCH™ was designed in hopes that it will attract learners to consider a career based on an Electrical and Computer Engineering (ECE) education, hardware and software engineering. The MENSCH™ can be used to learn about all kinds of electronic components and all kinds of state-of-the-art programmable logic. Operating at 3.3 volts provides for easy connectivity with various state-of-the-art electronic components and modules such as sensors and actuators. Operating at 5.0 volts provides easy connectivity to 5.0 volts electronic components and modules.

W65C265S MCU operating at 3.6864 MHz
Works at 3.3V or 5V (Cable not provided), giving access to a wider range of sensors, memories, FPGAs, etc.
Serial Terminal Programming Interface Serial Port #3 (P66/P67/P56/P57) NOTE: Requires external FTDI FT232 or similar cable/board (not included)
8 LEDs connected to P7x
2 – 18 pin connectors plug into standard breadboards for quick prototyping. Signals accessed are Ports P0x (A0-A7), P1x(A8-A15), P3x (D0-D7), Serial Ports S0 and S1; 1 x 4 pin Connector with PHI2, WEB, NMIB and IRQB signals for expansion.; 1 x 4 pin Twin Tone Generator Connector (Driven by TG0/1)

$29 is a much more realistic price (previously £89 from Mouser?) - and what you get is a surface-mount SoC on a breadboard-friendly carrier PCB.

Otherwise you'd need a patch wire to the LEDs to get a clean chip select signal

Now if only they would sell their C compiler at the hobby level, this could go someplace.
Last time I tried to puchase a license, I was hit with a "not for hobbyists" brick wall.
I found that extremely odd considering the efforts to drive interest at the hobby level.

Brad

I'm not sure if you can add external RAM. The address bus, data bus and control signals are routed to the pin connectors but the qualifying chip selects are not -- they are being used to control the LEDs.

Port 7 has a Chip Select register (PCS) that is used to enable Chip Selects (CSxB). A "1" in bit x of PCSx enables Chip Select CSx- to be output over P7x while a "0" in PCSx specifies the value in the output data register is to be output on P7x. Port 7 data register is set to all "1's" after Reset, and PCS is cleared to all "0's" after Reset.

CS7B -- 4M -- (C0-FF) -- User Memory

So, if I were to try and access memory in the C0xxxx to FFxxxx range, then the CPU would automagically (assuming proper configuration) trigger CS7B?

So, that the memory map in Table 1-5, that's a static map?

Can you simply mimic the proper CS signaling through glue logic off of the Address bus? Of course for this thing, they only expose the lower 16 address lines. Maybe, because of that, the lack of CS is moot?

Without the upper address lines there is no much fun. And you have to pay attention that your external devices don´t collide with the internal ones. All of this has been done within the 265 and you could use it if they have provided the /CS signals to some pins

Does it have to be QFP? I mean, will PLCC do? Because they have that here: Link.

The MENSCH™ has a built in operating system called a “Monitor”. The Mensch Monitor™ interfaces through a USB cable providing power and development through all kinds of “Terminal Emulators” found in most computers, PCs, Macs, tablets, and Smartphones.