Not in the HF bands. The Nyquist rate puts an upper limit on the symbol rate you can transmit in a bandwidth-limited channel: twice the frequency (in Hertz).
For amateur radio, there is only 500 KHz in the entire 80-meter band, and 300 KHz in the entire 40-meter band. Your fellow hams would probably not appreciate it if you used the entire band for your broadcast.
You could also increase the bit rate by switching to a more complex modulation scheme like 16-QAM (4 bits for each symbol) or even 64-QAM or 256-QAM. But, these are extremely susceptible to noise, and generally are used in closed systems like digital cable and optical fiber.
This is just an idea I had. Even being able to transfer text would be good, the receiver could always generate the PDF or whatever file type is convenient for the local BBS.