Excellent idea.  Negative measures are also useful when you want to have a correct measure account but the audio includes an audible count-in.

skinnybones lampshade
I have hoped for this feature for years.
 
Edited to add: This comes in especially handy when you're reading from a written score. Say you're looking at measure 256 in the score and want to cross-check that same place out on your recording- Did I play the triplet smoothly there? Did I get the right feel?
 
If the same measure in the score could actually always be found at the identical measure number (in this case,256) in the Sonar recording, too, what a treat! No extra steps.
 
Of course it isn't hard to remember or look up how many measures you left blank and/or containing introductory material before the measure marked as "1" in the score at the beginning of your recording of that particular piece. Then you only need to add that number to the measure number in the score (256) to figure out what measure you should go to in the recording, but wouldn't it be great not to have to?
 
So simple, straightforward and clean!  One less little frustration. One tiny obstacle less between you and the music.

It's all about speed to me.  I use GOTO measure a lot and I'm following a score to use punch in and punch out.  Having SONAR synced up to measure numbers is a must for me before I give up PT. 

a huge +1.. 
 
which is what i put comments on this same topic, year after year..
 
external midi devices need a measure or two to get setup and in sync.. songs start with pickup notes.. etc etc

If you are like me, you have songs that have things, be it sound effects or transitions, that start BEFORE the song actually starts.  It would be nice if I could set the "start time" point on the timeline to reflect this.  That way my measure counts match the actual song structure, so 01:00:00 is the start of the actual song, not just the start of the project file where the sound effects start.
 
Below is a very rough mark up. :-)

 
 
 

Smart idea, I give my thumbs!

Yes!