Glad to hear that 32MHz will work. If you want to see how you can quickly update your XLR8 board to run at 32MHz, check out this video:
There’s nothing that we can do about the available RAM based on the FPGA that we are using for XLR8. You can add an external EEPROM to the 8-pin SOIC footprint that is provided. I don’t know if that will really solve your desire for more RAM, though.
Standalone Xcelerator Blocks for communication interfaces such as UART, SPI, I2C are in the queue right now.
We just released our Quadrature XB late least week, and will be moving forward on the communication interfaces soon. Once the UART XB is out, you could build an FPGA image with multiple UARTs via the OpenXLR8 flow.
Hope this helps!