Garmin chose Sun 'n Fun 2016 to introduce their new EFIS unit that can serve well as a backup display for airspeed, altimeter, artificial horizon, vertical speed, slip/skid ball, and HSI. Heading information must come from another source, or as a stand-alone unit GPS ground track will be displayed instead of magnetic heading. Its 3.5-inch display will easily fit in most panels. I found it easy to use and was impressed with its suggested retail price of only $1200.
The G5, when tied to a larger Garmin G3X unit, will also display CDI and glide slope information.That is a lot of capability for such a small package, It is, of course, experimental only.