Even if it doesn't have voice capability (other than SIP/VOIP), I'd still love to see this come about.

My ideal:

1) take the Sidekick Slide type format (screen slides, shoulders don't, dpad and other functional buttons on the shoulders).
2) enlarge it to have a screen the size of the N810.
3) give it a tilt screen instead of a kickstand.
4) charge via USB.
5) WCDMA in the 850MHz, 900MHz, 1700MHz, 1900MHz, and 2100MHz bands
6) Quad-band GSM, but maybe only for SMS/MMS/data ... I don't care one way nor the other about voice (on GSM or WCDMA).
7) Port the E series Symbian apps to it.