From what we are seeing, the A4000 may be the best bet if we believe the graphs that have been posted. The E4000 and E5000 has been posted on Crinacle's list, the E5000 is warm (so it is similar to the sound that the E3000 is) and the E4000 is V shaped. I am not sure if the E5000 has better high mids or treble.
The A4000 seems to add the high mids and treble emphasis you seem to be looking for but nobody has it yet as we are waiting for it to be released in North America and Europe. The UK already has it from I am aware of. Might be good to be aware of it as it seems like an upgrade to me. I am a fan of the E3000 as well.
@davidmolliere did an experiment a while back: link
But yeah, the Piano Forte are not supposed to be used like that. Still wish I could get them one day if the fit would be good, but as they are being discontinued that will probably not happen.
Same impression here, E5K is darker than E4K, but more musical and pleasing with the right tips and cable. Bass, mids, imaging and soundstage are great on the E5K. Watch the synergy with your source and give them enough juice. The E5K is a demanding IEM, the E4K a bit less. Still, we all hear differently.