I mentioned this subject (EFIS compatible with FLARM) to a friend
He has his own company Midwest Panel Builders www.midwestpanels.com
He just emailed this to me. I would like to pass this along to anyone interested.

"You mentioned FLARM to me in the glider community. I put together an EFIS system that will work with FLARM

"MGL iEFIS MX1: $2,655
Weight: 2lbs
Current draw: .6 amps

It has airspeed, altitude, attitude, heading, can work with many COM radios (and new ones are cheap), and can take FLARM inputs. Lighter than an airspeed indicator and altimeter and has a low enough current draw to run for 24 hours on a standard 12AH lead acid battery. Throw a lithium battery in and now you have an even lighter solution. GPS Built-In too.

Cannot be used on certified aircraft however."