I don't think there are that many. The usual suspects you most likely have found already, the Sony Professional Walkman series, including the only Sony player with Dolby C and a line-out DC2.
The D6C has Dolby C and a line out as well. The D6 and D3 also have line outs but don't have Dolby C. They all sound very good but my personal preference is the D6.
I'm hearing you @Deb64. Whilst Dolby and Record Calibration sets your deck to make the best recording on any given tape it always comes at the expense of some of the higher frequency sounds to my hearing anyway. Once you've fixed those hybrid (potted) modules on a D6 you've got a great Walkman with that legendary tape head that was not used for long on the D6C production line.
If your specifically looking for a "Walkman," I don't know but the Panasonic RS-J3 has real RCA jacks built into it. If your looking for something portable that might sound good with component stereo, check out the Field Recorder Thread with models from Sony, JVC, Marantz (Superscope), Technics and more. They were heavy duty but also made to easily use with your home or work stereo with RCA jacks.
+1 for field-recorders when it comes to line-out. Even though the D6C and D3 etc are perfectly fine, the TC-D5M is my go-to for hooking up to an external amp and speakers.
