Some cars have procedures for getting data from the LED trip meter, though I don't believe any show DTC's (e.g., my old Focus had a sequence to follow before the display would indicate certain engine parameters.)
I can't imagine it would be hard for manufacturers to incorporate another bit of logic to allow DTC's and nothing more to be displayed in the same manner. This alone would save tons of time and help immensely with trouble-shooting intermittent CEL's, where the code clears prior to being scanned (e.g., my old Focus would throw a CEL often, but cleared while driving, and did not remain on for the first three trips to the dealer - very frustrating!)
I still think that the CEL has its place, energizing solid for minor issues and blinking for major, though it would be nice if a specific level of severity could be indicated (e.g., emissions equipment code vs misfire code.)
A bit off-topic, but something similar would be nice for all detrimental issues, such as over-heating and charging system casualties. One step more would require something like an acknowledgement (via push-button or voice command) that the driver realizes that further operation of the vehicle could result in catostrophic failure, such as in the case of an over-heating engine. How many stories have we heard where friends or relatives continued to drive while the engine coolant temp gauge silently warned of impending doom, unbeknownst to the operator. Some new cars don't even have the dummy gauge.
Sorry for my digression, but it seems that data like the aforementioned could easily be incorporated into newer info-tainment systems, if not every vehicle, even if only simply.
