The final set of connectors has not yet been settled. What there is currently, is:
* C65 keyboard
* IDC header with keyboard pins (will probably be changed to a C64-compatible keyboard connector)
* 24-bit VGA out
* 24-bit HDMI out
* 34-pin standard floppy drive connector
* C64-compatible cartridge/expansion port
* 3x PMOD connectors (common on FPGA development boards)
* 50-pin IDC expansion connector
* C= serial floppy drive port
* Connector for USB serial debug
* Power switch
* Reset switch
* Joystick ports
As I say, the final list of ports may end up somewhat different. What is likely for now, is that if you want a tape or user port, these will probably connect via a PMOD or the 50-pin expansion connector. The lack of these physically large ports all comes down to cost. The bigger the PCBs, the more expensive.
We do hope to add sockets for SIDs. Worse-case scenario, they will be usable from a cartridge.