I made a little progress today.
I learned how to build a copy of my vgabios and build a new image rather than use the one that came pre-built with the kit.
I've found a configuration that under both ADLO and direct IDT will actually enable a VSYNC. No video output yet but at least its a start. I almost didn't catch it. It appears to be hung but after about 15 seconds or so something times out and the familiar *foush* of the monitor kicking out of powersave can be heard. Elfboot then runs and boots up my system.
The vgabios emulator still chokes on the image though. The unsuported write string call somehow causes the bios to execute a halt. Is there a way I can set up a breakpoint and then drop to single stepping?