My suggestion,...
My suggestion would be to score
a DP-02cf or Fostex MR8-HD and use the 488 to do front-end mixing to the digital recorders. Choose the DP-02cf for easy purchase price & if you can live with 2-simul recording, but grab the Fostex if you forsee yourself needing up to 4-simultaneous track recordings.
These newer style digital units lack an input mixer, so IMO the 488's mixer section would fit the bill nicely. I can't recall if the 488 has 4-buss outputs??
I looked thru all my manuals, and of course it was the very last one in the bunch.
Use the 488's Group Outs 1~4 for mixing up to 4-track simultaneous recording to the MR8HD, (same for the MR16HD). Use 1-2(L/R) Group Outs for the DP-02cf.
Maybe look at the MR16HD for a good sized upgrade. For the same cost it gives you 2x more tracks than
the DP02(std).
Note: I don't normally recommend Fostex recorders on the Tascam forum, so pls excuse me on that. Also, I've been recording w/Tascam 244 Portastudio mixer front-ending to a DP02cf lately, to good effect and it works fine. 2-simul doesn't limit me as it's only 8-tracks max on that unit. My pet peeve about the latest all-in-one'rs is the lack of input mixer, so I think this technique's a must! It makes the newest units livable, 'cause I'm old school about input-side mixing in production. YMMV!
If u want a slightly better output-side mixer, stick with the Tascam unless you prefer to mix in-the-box. The Fostex MR8 or 65 lacks tactile EQ altogether, but has 33 EQ presets that can be printed to tracks or on output. I'm not sure if I'd like EQ presets, but I've not heard them, (they could be okay). I'm partial to Tascam for the most part.
Alternately,... as RRuskin stated above,... use your 488 mixer section to front end directly into the 'puter/interface & recording software. The decision may vary on if you want to go desktop 'puter style or keep to the Portastudio format. Then there's laptops but that seems more of a hassle to me,... again YMMV!