Ok let me ask here, not sure if I read this right? On the video output of the VAX is it just a single BNC connector? if so then any TV display with an rca input (not 75ohm) should work just fine. BNC is used alot still on Pro end video equipmemt and adapters to go from BNC to RCA is easy to find.
on the last link that was posted there is what apears to be a VGA output the pins are labled:
Video Connector (J5)
1 - vid_red 2 - color_ret 3 - mono_ret
4 - +5VDC 5 - mouse_rcv 6 - kbd_grnd
7 - ground 8 - +12VDC 9 - vid_mono
10 - vid_green 11 - vid_blue 12 - -12VDC
13 - mouse_xmit 14 - kbd_rcv 15 - kbd_xmit
Not sure if this is a standard VGA output but if it is VGA monitors are still availavle.