Adapt Sun-3 color board to Sun-4?

[Mike Persons]

This may be totally impossible; in which case a thousand apologies.
However:  

We have a 3/60 with your basic color monitor - no fancy graphics.  We also
have a 4/65 with a mono monitor, and we want to use the color monitor on
the 4/65.  A color board for the 4/65 costs $1675 from Sun (including the
A discount).  Is there any company out there that lets you use a Sun-3
color board with a Sun-4?  I know they use different busses; aside from
that I have no idea.  Does anyone else?

Please e-mail unless you think it would be of general interest.

Thanks
Mike