It sounds like you're still looking for a DGX model. There were four series of DGX:
DGX-2xx series
DGX-3xx series
DGX-5xx series
DGX-6xx series
If you want 88 keys then you want either the DGX-5xx or DGX-6xx series.
I believe the DGX-6xx series has better weighted keyboards as far as graded hammer scale action, and most DGX-6xx models have better polyphony.
But if those aren't critical issues then consider the DGX-5xx series, too. Oddly enough, in certain respects the DGX-500 looks like it might be better than the other DGX-5xx models as far as its voices, because it has 480 XG voices (as compared to 361 XGlite voices on the other models), plus it has 38 DSP insertion effects that can be applied independently to the Main Voice and/or Dual Voice (the other DGX-5xx models do not). But the DGX-500 has a disk drive rather than a USB port, and MIDI DIN ports rather than USB-MIDI, so you might want to take those facts into consideration.
Note that some of the DGX models are also available as YPG models; they're the same keyboards, just with different names for export purposes:
DGX-500 - 122 panel voices, 12 kits, 480 XG voices, 5 DJ voices - polyphony 32 notes
DGX-505 - 121 panel voices, 12 kits, 361 XGlite voices - polyphony 32 notes
DGX-520/YPG-525 - 127 panel voices, 12 kits, 361 XGlite voices - polyphony 32 notes
DGX-530/YPG-535 - 127 panel voices, 12 kits, 361 XGlite voices - polyphony 32 notes
DGX-620/YPG-625 - 127 panel voices, 12 kits, 361 XGlite voices - polyphony 32 notes
DGX-630/YPG-635 - 130 panel voices, 12 kits, 361 XGlite voices - polyphony 64 notes
DGX-640 - 142 panel voices, 12 kits, 381 XGlite voices - polyphony 64 notes
DGX-650 - 147 panel voices, 15 kits, 381 XGlite voices - polyphony 128 notes
DGX-660 - 151 panel voices, 15 kits, 388 XGlite voices - polyphony 192 notes