One thing that hasn't been mentioned yet is that there were a few auto-reverse 1/4" decks made. Certainly by Akai, Sony and TEAC. I think there may have been a Pioneer too.

As for the Akai 4000 DS, my comments apply only to the original. The Akai GX 4000 D(S) is a different animal and performs much better as it has the GX heads from machines higher up the range.

As for demagnetisers, there's one here for a riduclous £39.99:

http://www.taperecorder.co.uk/accessories.htm

Don't whatever you do pay that. I have one just like it (but for the colour) which you can have for a tenner.

Nice Sony here: http://cgi.ebay.co.uk/Sony-TC730-Reel-to-Reel_W0QQitemZ5826319337QQcategoryZ116868QQrdZ1QQcmdZViewItem#ebayphotohosting

Nice (sold) Akai here: http://cgi.ebay.co.uk/AKAI-GX-4000D-Stereo-Reel-to-Reel-Tape-Recorder_W0QQitemZ5825172253QQcategoryZ109002QQrdZ1QQcmdZViewItem

There's a Revox A77 here: http://cgi.ebay.co.uk/Revox-A77-reel-to-reel-tape-recorder_W0QQitemZ5826502437QQcategoryZ109002QQrdZ1QQcmdZViewItem

Bet that'll fetch a good price, as will this B77: http://cgi.ebay.co.uk/REVOX-B77-MK-II-HI-SPEED-HALF-TRACK-REEL-TO-REEL_W0QQitemZ5826520105QQcategoryZ109002QQrdZ1QQcmdZViewItem#ebayphotohosting

You've got me tempted now