wikipedia article on the tascam four track
ahhh, my beloved cassette four track. here's the deal if you see one of these, and it works, you better snag it. they sound great!
one of the most profitable projects i've ever been involved with was made on one of these. the band i was in rented one from a local store, and eventually paid it off with the rentals, the silliest most expensive way to get a piece of gear, but we were broke, and loved the thing. over time however the main project done with that deck is still one of the best money makers i've ever been involved in.
with all the advances in mastering, these things are more viable than ever. the hep thing about four tracks is, you have to bounce, which is like pre-mixing, which is destructive editing, which forces you to make decisions.
personally i would be more interested in hearing just about any music ever made, recorded on one of these, over the pro-tools trip.
[ hey artists, if you make your music in the box, and then make cds and mp3's only, you get to participate in what i call how the man killed the art.]
take a look at that wikipedia list, there's some hep records on there. and there's thousands left off that list. the funny thing is, there's producers and plug-ins valued in the tens of thousands range, that you can instantly replicate for free with one of these units haw haw.
you can still get parts, and you can still get blanks. and you can still find them on ebay. heck these things are like sailboats and shotguns, there's plenty of them laying around unused. pilfer around and see if you can dig one up.