Traditionally, only NURSE is transcribed as an r-coloured vowel in North American English, but I think there may be others in my accent as well. My NORTH/FORCE vowel /or/ sounds r-coloured to me, and I think the /r/ following it may even be elided in some situations. I think START is also r-coloured but it doesn't lose the /r/. I've heard of this happening in the West Country, but I've never seen it in any descriptions of NAE accents.
You can take a listen here: http://media.putfile.com/Comma-Passage
north ["nO`T] (0:10)
morning ["mO`.nIN] (0:17)
form ["fO`m] (0:37)
normally ["nO`m@.li] (0:41)
My dialect does not have r-colored vowels at all, having rather just a syllabic [R=] practically phonetically identical to coda /r/ [R]. But it does have other effects upon vowels by /r/, aside from the usual vowel mergers. In particular, the vowel /a/ is realized as [A] or, by some, as even [Q] when followed or *preceded* by /r/ (or, as [V] when a following /r/ is followed in turn by a fortis obstruent).
How do you manage that? So "stork" is "stowerk" for you?
"Traditionally, only NURSE is transcribed as an r-coloured vowel in North American English..."
What about r-colored schwa?
<<What about r-colored schwa?>>
True, but there is no contrast between them in my dialect. They can be regarded as stressed and unstressed allophones of /3`/. I tend to transcribe it with /@`/ for the purpose of cross-dialectal compatibility.
>>How do you manage that? So "stork" is "stowerk" for you?<<
No, that's just ["stORk], without any r-colored vowel. What I meant is that I have no r-colored vowels in my dialect, with both [3`] and [@`] being replaced by just [R=], which is a syllabic approximant rather than an r-colored vowel.
I think I may have a minimal pair between r-coloured /or/ and /o/+/r/:
Of course, 'coroner' can also be pronounced with three syllables: ["kO`r/@n@`].
Coroner always has three syllables. Or else you'd be saying "corner" ... and wondering what that had to do with dead people.
Can you record that? Just to see if I could make out "coroner" with 2 syllables without any context to make it evident.
I always pronounce "coroner" with three syllables, and I'm Tory-torrent unmerged, so it uses a different vowel from "corner" anyway: