There was a yellow ute with black and multicoloured tray, in some magazine a few years ago that had a silvia dash in it.
Don't remember how far into they went and I have way too many magazines to look through and find it...
But yeah, anything is possible... Depends on how much work and resources you have...

yeah it is possile using the dash as in instrument! part only... when running a ca18det computer u just have 2 hook dash up 2 it! mate had it done in 1200 ute! looks neat! im thinkn of making up custum dash autometer with metal like serounds.. much more reliable!

It's been done in a 510. Click

I have seen one in a CA18DET 120Y,when he said he used the whole front cut he wasn't lying. Looked like a lot of work though.

Well, in the 'anythings possible' vein, I guess you could....
The Silvia is substantianly wider than a 1200, so if you didnt want to take a hacksaw to the dash you'd have to run it lengthways between the front seats, or praps just keep the front windows wound down....

is it true that you can fit a silvia dash in a 1200?