Leon wrote:

Say your board is 12" wide, most all but the smallest of gauges have
to hang off the front side of the fence to allow room for the board
to sit. The higher end Incras typically stick out way back behind the
fence. Basically I am not too sure how much of the guide bar ends up
being out of the slot.

You might try a table saw sled.

Here's one:
http://www.mywoodprojects.com/plans/crosscutsled.aspx