Of course, in this day and age, it only makes sense to add a flat panel color display to your SE/30. Not sure of the connection caveats though, as I've never tried it. But smaller, low-rez LCDs are not that expensive anymore. They may be rather hard to find in the US, but they are commonly found here in Japan.
I still think a nifty color screen upgrade would be to put an LCD inside the SE/30. It's a major hack and not for the purist among us. But I am mainly speaking about a screen swap versus a brain swap. The logic board and all the electronics would be stock (with the exception of a video card that would be needed and possibly a secondary PSU to drive the LCD. Since some people have replaced the guts of a compact Mac with a Mac Mini and LCD, I would think that it should be possible to retain the internals of the SE/30 while simply swapping the CRT technology for color LCD. And it would be especially fund if the resolution was switchable, with one choice being the native resolution of the 9" CRT, perhaps with a secondary choice being 640x480.