Ah, B77 was my object of desire, too (in the times, some 20-25 years ago, when I was doing light and sound for several amateur theatre troupes). It was a standard fixture (usually two of them) in theatres we were performing in, but I was recording and preparing tapes on a contraption of Polish manufacture (a copy of an ancient Grundig or something). I still have somewhere multicoloured blank tape and cutting and splicing gadgets...

Several months ago I learned that a girl I knew very well in those times used to work in Studer recently (and probably could have bought some old but working Revox machines), but she got 'downsized' in the meantime....

As for the value of those machines: purely sentimental, of course, but isn't it enough?