I used FT245 the first time a few weeks ago. I like it; it is simple to interface, very very fast, and you can boot from it so a simple computer made of FT245, RAM and 6502 is possible. The FT245 interface is at lower left of the schematic. One thing to watch out is its read strobe is active low ...

Yes cpld is the way to go to achieve a compact design.

This is a true 8bits usb interface. This chip is rarely used. This is strange since it is very to interface, and I do not have to add or synthesize an ACIA.

I assume the 4-pin header next to CF disk is the I2C connector? Do you plan to drive graphic display with I2C? The 128x64 OLED display works well with I2C.
Yes absolutely, I have a got a 128x64 OLED display, but not yet played with it.

I've also found 30MHz as the upper limit of CF interface ...

Hello,
My goal was to have a compact 65C02 SBC (PI form factor) I can use from my sofa. So this is a tty only setup. I was inspired by plasmo designs with CompactFlash. I started with the 6502 utilities he did for its frugal 6502 board.
Without CompactFlash and MMU, the board was tested at 30-35Mhz ...