The 488mkII is a good machine,...
but it only records 4-simul-max, and as stated before, does not have individual TAPE OUTs or DIRECT OUTs. Even at 17 lbs, the 488mkII's a cool Portastudio for 8 tracks, but it has less overall headroom than a larger format.
The Tascam 238 is a table-top or rack mount cassette 8-track, that has 8-INs and 8-OUTs, and can record up to 8-simul-max. You could potentially use the 238 cassette-format 8-track, and still dump the individual tracks to an 8-IN soundcard on the 'puter, [your stated purpose], however, the 238 requires an external mixer. The 238 w/mixer could potentially be 'roadcase-mounted' for portability, but by itself, the 238's not necessarily considered a 'portable' unit.
Also, the Yamaha MD8, minidisc 8-track, is very similar Portastudio-like design to the 488mkII, with a very similar onboard mixer, but the MD-8 has a midisc recorder instead of cassette. The Minidisc format will definitely have more headroom and clarity than a cassette format. Unlike the 488mkII, the MD-8 will record 8-simul-max, and has 8 individual MD-TRACK-OUTs. Of course, the MD is 'data' recording, and gets away from the original premise, that you want 'analog'.
Back to analog, there's the reel-1/2"-8-track format, and that's a big step up from cassette, but unless it's rolling/roadcase-rackmouned, it's not considered portable. A 1/2" 8-track, such as a 38 or TSR-8, will also require an external mixer, but will blow away a cassette, fidelity-wise.
Once in a great while, you may pick up a 38 for about the same amount as a 488mkII, and dollar for dollar, the 38's definitely more audio bang for your buck. F/I, I've gotten a 38 for as low as $299, and also an M30 mixer for as low as $150, [a total 1/2" system for ~$450], and I've also seen 488mkII's sell for $450.
There's more, such as the analog Tascam 388, with a complete Portastudio-like all-in-one design. The 388 records 8-simul-max to 1/4" reel tape at 7.5ips, and with a full blown 8x8x2 integrated mixer, the 388's an appreciable step up from the 488mkII. The 388 has a full complement of INs & OUTs, with 8 TAPE OUTs, plus much more. However, at almost 90lbs, the 388's portable, but it's a real load for one person to handle alone. The 388's easiest when lifted by two people, but it's a great machine, for sure. Likewise, I've also seen the 388 sell for comparable prices to the 488mkII, ~$450.
IMO, as used analog gear goes, there's still a few good choices in 8-track. I think it's a buyer's market on analog, and prices on decent used gear seems to still be dropping.