Is just adding #5 a common practice? As in:
D Gb Bb C E G = D11#5
I've seen it also as D11+. Is there a more conventional way to notate this?
If the chord were a simple triad - D F# A# - then this would be called D Aug (augumented). Adding the C would make it DAug7, adding the E would make it DAug9, and adding the G would make it DAug11. Sometimes the plus sign is used instead of Aug, so calling this D+11 (but not D11+) would be possible. Unfortunately, D+11 tends to give the impression that this is a D chord with an added 11th (but not 7th or 9th), so DAug11 would seem to be best.