I noted that there is an unsupported version of FreeRTOS for the Blackfin.

What are the odds that TCP & WebServer capability can be added? How much effort should be expected?

We have a Blackfin platform in need of an RTOS and these capabilities.

Also we are needing to read and write files on an SD card. This seems to be a capability of FreeRTOS+IO...? Would this be available to the Blackfin or would this require significant porting.

The featured FreeRTOS+IO demo uses the Chan FatFS and lwIP - both of which are third party open source components. You will find links on the featured demo page. Those two components can be integrated into a FreeRTOS application without the need for the FreeRTOS+IO layer, there are several examples available on the web or the FreeRTOS+IO example can be used as a reference.

Regards.