Gee,... how'bout a Porta-studio?!
There are probably at least a dozen genuine Tascam Portastudios to choose from, and almost all of them will do the type of recording you've described,... with only one exception I can think of:
the MF-P01,... so avoid that one.
That leaves all the other Tascam Portastudios to choose from,... models and features too numerous to mention. Search "Ebay/Tascam" for further info, or "Tascam" on any of those new online music equipment retailers (musiciansfriend, etc). Find the most high quality USED 4-track Portastudios as: Tascam 244, 246, 464 & 424mkII. Find the most high quality NEW 4-track Portastudio as the Tascam 424mkIII.
Also, I beg your pardon, but you've detailed the most basic & rudimentary recording possible, which [IMO] would include almost every other recorder out there,... including your standard home-console cassette deck and Minidisc recorders. I'd suggest some nice Technics dbx cassette decks (Ebay/Technics cassette), or any Sony Dolbyc/HX-Pro stereo cassette recorder, (Ebay/Sony cassette or new/retail). Also, the Sony MDS-JE510 & MDS-JE320 are a couple of the nicer Minidisc recorders, (Ebay/Sony Minidisc).
The way you describe your recording needs, pretty much leaves it wide open.
I'd offer these parting shots,... search Ebay for "Tascam 234", for a leading design in 4-track cassette recording, that's a "Syncaset" and not a true "Portastudio".
If you want something that goes way beyond cassette and Portastudio recording, I'd suggest searching Ebay (again) for "Tascam 34B". There are all sorts of vintage 4-track/Stereo reel recorders, too numerous to mention,... but the bulk of them I'd recommend would be "TEAC" and "Technics". Note: Almost all reel/reel recorders would be Ebay items, with only a couple exceptions.
That's enough ideas to keep you busy for a while, and to commit at least a couple hundred dollars to,... (heh). A lot depends on your sound quality requirements, portability requirements, and budget.
Good luck!!