Alternatively, you can connect the exposed pad to a floating pad with vias on board for heat dissipation and better pcb mounting. We will take note and update this information on future revisions of the datasheet.
ADI has A/D & D/A Converter Combinations but the parts don't meet your requirements so we have to do this the brute force way. I would be able to assist on the DAC part. You may want to check the following parts: