My 2488neo DOES allow this - you record a stereo track, and though they can't be separated into single tracks, BOTH halves of the stereo track are treated as independent and have have their own panning control, EQ's, yada...
For the benefit of future 2488 & DP-24/32/SD portastudio owners coming to this thread:
2488 NEO
(from the 2488NEO OM Pages 29, 32, and 33)
Adjacent track channels and input channels can be linked. By linking channels, the parameters of 2 channels (usually the left and right channels of a stereo pair) can be controlled simultaneously. A linked track pair can be formed with an odd-numbered channel and the even-numbered channel immediately to its right. For example, channel 1 can be linked with channel 2, and channel 5 can be linked with channel 6. The left fader of the linked pair controls the levels for both channels).
When track channels are linked, the following parameters can be controlled simultaneously: Faders (the left fader of the linked pair controls the levels for both channels); EQ; Digital pad/gain; Effect send levels and pre/post selection. Pan Control: Linked channels still count as two channels.
When Input channels are linked, the following parameters can be controlled simultaneously: Internal fader values; EQ; Digital pad/gain; Effect send levels and pre/post selection.
Tracks 13–24 form six stereo tracks (13-14, 15-16, 17-18, 19-20, 21-22, 23-24) with each stereo track being controlled by a single fader. Stereo tracks are always recorded as a pair.
Individual Input channels can be assigned to a stereo pair (e.g. Input "A" -->Track 13; Input "C"--> Track 14). Recording on only one channel of the pair is impossible. When assigning a single input channel to a stereo track, the same input is assigned to both tracks. Example: assignment of Input A to track 13; A --> 13, 14.
DP-24/32/SD
On the DP-24/32/SD, all tracks (Mono and Stereo) can be
linked using the Fader Group function. Each individual track retains EQ, FX, Fader, Send, Pan, etc. controls. Master fader level for the Fader Group is controlled by the left-most track of the Fader Group.
For the Stereo Pair Tracks (13/14, etc.) EQ, FX, Fader, Send, etc. act on both Tracks of the pair. The stereo Balance Knob adjusts the level of one side of the paired Tracks relative to the other. On the DP-32/SD, the Stereo Tracks can be switched to Mono operation.
Inputs A~H cannot be linked except that the Dynamic Compressor can be linked to two adjacent Inputs (e.g. "A"&"B").
Only adjacent Inputs can be Assigned to a stereo pair (e.g. "A" & "B" ---> 13 & 14). On the DP-24/SD, if only one Input is assigned to one of the stereo tracks, then that Input is assigned to both tracks (e.g., "A" -->13, results in "A"-->13/14), creating a Mono signal, and the stereo Balance Knob functions as a Pan control.