While on the ramp the other day, I was checking out my FBOs new Garmin equipped 182. I asked my instructor if she had flown it yet, and she said she couldn't because she needed 10-hours of glass cockpit instruction before she could. I'm not sure if this is the FBOs requirement, or what, but they do have a set up in the classroom with a cardboard cockpit cutout with the two garmin screens for training purposes.
...depends on what rules you are flying under. Part 135 requires documented training, and a sign off (usually done during a recurrent checkride) on whatever box you use for navigation. in the case of a pro-line 21 cockpit, the FMS 5000 requires an additional sign off than, say a KLN 90 in the two tube EFIS style cockpit.
Read the latest instrument PTS. There are references to the TAA or technologically advanced aircraft. Since PFD's don't allow for "normal" covering of instruments for partial panel ops, there are provisions for the student to be able to demonstrate flight by reference to instruments under a primary instrument failure.
But no endorsement required. Probably will be soon, according to some at our FSDO. Purely insurance-required.