I just finished taking pictures and dumping the firmware from a 730X terminal but it turns out it has a Starlan and not an Ethernet interface. It would be nice to get a firmware dump from an Ethernet card. A start of a 630 driver is in MAME.
http://bitsavers.org/pdf/att/730/730X It also appears the keyboards for the 630 and 730 aren't backwards compatible with the other 6xx products and the 5620. 5620 keyboards need -12v which the 630 or 730 don't supply, and the 610 keyboard doesn't appear to work either. Josh took a couple of pictures of his 630 keyboard and even though they look similar, the earlier keyboards were made by Teletype and the 630 is made by Keytronic.