The Hamamatus SPI board is up and running! The design files include the sensor board and a mating carrier for a Teensy 4.0 It seems like it would also be a good match for the UNE and perhaps more of the newer Arduino boards.
As a reminder, this is a self contained board in the sense that it has its own front end, a high precision low noise differential amplifier, and a 16bit 1MSPS ADC. The external interface is the SPI and some logic signals from the sensor. There are logic converters and a VDD input that allows the board to interface over a range from 1.7V to 5.5V. Power for the sensor and amplifier is 5V, which in this instance is provided by host MCU carrier.
The bag of part is around $50 and I have heard that the sensor is available for around $100. So it is bit more expensive compared to the Toshiba. But the factor of 10 lower noise floor means that in principle at least, it can cover an intensity range not accessible to the Toshiba, and it has a dynamic range such that a 16 bit ADC actually becomes a rational design choice.
The firmware (i.e., "sketch") is written largely to the standard Arduino libraries, with optional register level enhancements for the i.MX RT (i.e. Teensy 4). There is a state engine that runs from a kind of secondary clock generated by the chip. Interrupt latency is important, and this is where some Arduino boards may have an advantage over the Raspberries. A little bit of bit fiddlin' can shave a 100 nsecs here and there and make the interrupt latency more constant, and get you to a slightly faster readout, but it is not necessary in all cases.
Here is the link the to the repo. The Python code already posted in the TCD1304 repo runs this board too, and I plan to soon post a C language utility and library that also operates all of the linear CCD boards that I am building.