Cursor as full screen crosshairs I have a 27" iMac running Snow Leopard.  In a wide range of applications I often need to use a straight edge to compare different values on charts, even sometimes charts generated by different applications.  To do this I have made do with clumsy solutions like creating a floating and transparent Sticky or using Shift + Command + 4.  I've also tried a small app called Crosshairs.

None of these things do what I really want.  Ideally, I'd like a full screen crosshair centered on the cursor.  Another way to think about this, it would give me a full height vertical and full width horizontal line that would show up over (on top of) any and all applications, just as a cursor does. Nice to haves it would give the coordinates of the display and have toolbar or right click access to turn it on or off.

Any suggestions?
While it has many more features than this, something like xScope sounds great for this. 

Some main features:


mirroring
getting on screen dimensions
rulers
guides
frames
crosshair