To save you some time, these are the two that are approved by the Center for Pet Safety. The safest options are on the expensive side, but as you noted in your post, there is no price on safety for our beloved babies!
SleepyPod Mobile Pet Bed
Sleepypod® | The safest pet company | Dog Carriers | Cat Carriers | Dog Harnesses
(also available on Amazon)
Pet Ego
Jet Set Forma Frame
Jet Set Forma Frame
To be used with ISOfix latch connection
ISOFIX-Latch Connection
The Pet Ego bag seems like a more all-around bag---good for the plane, car, more subtle design, but the car system seems more complicated then Sleepypod. We went with Sleepypod because dogs can see out 360 degrees and my two really cannot stand to be separated. If it were safe for them, we would have them in one carrier, but it isn't, so the next best thing is them being able to see each other