Allison wrote
          Tu55/56 the 3/4" tape on reels Most PDP-n
before 1973ish 
And don't forget the original 555 transport, and the LINCtape.
          Tu60    phillips digital cassette PDP-8,
PDP-11 mostly 
I've never seen this referred to officially as DECtape.  It was
called
DECcassette.  Since this was not a block-addressable random access device,
it is substantially less like DECtape than the TU58, and couldn't be used
as a "system device" for OS/8 or RT11.
          TU58    DC100 cartridge, DEC unique format.
PDP-11, VAX730, VAX750 
DECtape II.
  I'd love to have a TU55/56 Dectape (the open reel
style). 
My arm could be twisted to make a tape available, but it sounds like you want
a transport, and they are hard to come by.
I've partially completed a caching SCSI controller for the TU56 drive.