For less than $1000 a Garmin 196 GPS with its 4 AA Batteries will not miss a beat.  The “Panel Page” has; for those of you who may not have seen it, a usable presentation of a HSI, VSI, Altimeter, Turn Coordinator and Ground Speed plus all the other GPS info.  Aviation Consumer Magazine has established the airplane can be flown with a Panel Page as the sole reference.  Seems to me this little piece of redundancy could be the most reliable and cost effective piece of safety gear aboard.

Steve,  That device is a great backup (I have a friend that uses it as his primary - the panel is his backup).  Every year brings another advance - WAAS, semi-precision non-precision GPS approaches and "glide slope" management.  Then there is the promise of LAAS and in-flight Presidential TFR displays.  My panel, designed in the last century (92), implemented in 96, and upgraded in 2001 (Garmin 430) will never be finished. 

 

Of course, we must keep practicing with these things so they work for us when we need them.  It is also the reason to over design the electrics - All the future gizmos will be electric.