In the TOPS-10 world, ANF-10 RJE stations could have card readers and printers.  The TOPS-10/20 DN200 also.

But most "RJE" station software on the DEC side made the foreign mainframe look like a batch queue, and you would submit a file to that queue.  The software (typically DEC 2780/3780 emulation for {TOPS-10,TOPS-20, VMS, ...}) would send the file to the mainframe from an imaginary card reader; results similarly to an imaginary printer (ending up in a .log or other file).  I suppose "virtual" would be the modern word for "imaginary", but it comes to the same thing :-)

On the KL based systems, the software was a combination of PDP-11 front end code (a dedicated DN20) and code running on the KL.  The KS used a KDP, though there was also a "DN22" remote station.

I don't know exactly what UNIX did - wasn't in that world much then.  But I wouldn't be surprised if the strategy was similar - user prepares a file, software does the code conversions to/from EBCDIC, and the usual lies told (er, device emulation performed) in both directions...  That would certainly have led to the emulation work you recall - especially given the fluid definitions of character sets at the time.  I don't recall the same efforts to offload development to UNIX as to the DEC proprietary systems - IIRC, compilers for legacy languages (COBOL, RPG, PL/I) came to UNIX rather later, and with less rich/performant implementations. 

In my experience, physical card equipment, as previously noted, was either a legacy/migration requirement, or simply a bureaucratic legacy "requirement".  The DEC value proposition was that cards were expensive, awkward, slow, and painful to create, modify/debug with.  Interactive TS solved those problems; the emulations were a medium of exchange between the legacy/enterprise systems and the more productive DEC systems. 

Readers: quite common.  Punches, much less so.

One last reply here, but CCing COFF where this thread really belongs...

On Thu, Feb 13, 2020 at 12:34 PM Timothe Litt <litt@ieee.org> wrote:

OTOH, and probably more consistent with your experience, card equipment was

almost unheard of when the DEC HW ran Unix...

You're probably right about that Tim, but DEC world was mostly TOPS/TENEX/ITS and UNIX.  But you would think that since a huge usage of UNIX systems were as RJE for IBM gear at AT&T.  In fact, that was one of the 'justifications' if PWB.  I'm thinking of the machine rooms I saw in MH, WH and IH, much less DEC, Tektronix or my university time.  It's funny, I do remember a lot of work to emulate card images and arguments between the proper character set conversions, but  I just don't remember seeing actual card readers or punches on the PDP-11s, only on the IBM, Univac and CDC systems. 

As other people have pointed out, I'm sure they must have been around, but my world did not have them.