BPJ> I'm also mulling on which available Unicode
BPJ> character to use for this sound.  While it
BPJ> would be reasonably easy to fake Y\ as
BPJ> Latin Letter Small Capital Y Bar with the
BPJ> help of a combining diacritic I'm nevertheless
BPJ> leaning towards using lowercase Greek omega, as
BPJ> being most similar to the symbol for this sound
BPJ> in Svenska Landsmålsalfabetet -- essentially an
BPJ> M\ with a short middle leg.

TM> If I'm not mistaken, that was/is used for some phonetic symbol so it might
TM> be best avoided. (The TIPA manual includes it and an inverted (upsidedown)
TM> small omega and comments that they come from the _Phonetic Symbol Guide_
TM> (Pullum and Ladusaw, 1996), but doesn't say what they represent it in; a
TM> closed omega is apparently an obsolete near-close near-back rounded vowel
TM> from the IPAs of 1949 and 1979.)

I find it odd that someone would cite the PSG as a *source* for phonetic
symbols; it exists only to document how symbols have been used in the
past.  I would expect any new project to use the IPA, with optional
Americanist or whatever modifications depending on whom one is working

Anyway, the PSG has this to say about the above symbols:

        OMEGA (ω): American Usage.  Proposed by Bloch and Trager (1942, 16)
        following Boas et al (1916, 10) for a higher-low back unrounded vowel
        between IPA [ɔ] (CXS [O]) and [ɒ] (CXS [Q]).  Other uses: Used
        by Wells (1982, xvii) for an unrounded [ ] (CXS [U]): semi-high
        back unrounded.  Comments: Not to be confused with <w>, <ɯ>, or <ɷ>.
        The IPA transcription corresponding to Bloch and Trager's [ω]
        is [ɔ̞] (CXS [O_o]) or [ɒ̝] (CXS [Q_r]).  Source: Greek alphabet,
        lower case.

        INVERTED OMEGA (not in Unicode): Proposed by Trager (1964, 16)
        for a higher-low central unrounded vowel — the same height as
        IPA [æ] (CXS [&]) but central and rounded.  An alternative to
        the [ω̇] (overdot omega) of Bloch and Trager 1942 (p. 22).  A
        Trager suggestion that never caught on.  A suitable equivalent
        IPA transcription is [ʚ̞] (CXS [3\_o]).

        CLOSED OMEGA (ɷ): IPA Usage: Formerly approved for a vowel
        between Cardinal 7 and Cardinal 8; approval withdrawn in 1989.
        Comments: This symbol was common in IPA transcriptions of
        English for many years, representing the vowel usually found
        in the Southern British English words <look>, <put>, <full>,
        and <good> (which in Northern British English occurs also in
        a large class of other words, including <mud>, <blood>, <guts>,
        <luck>, and <muck>, where Southern British has [ʌ] (CXS [V])).
        The IPA had always sanctioned the use of [CLOSED OMEGA]
        interchangeably with [ ] (CXS [U]) . . . , but Americans had
        never used [CLOSED OMEGA], and in 1989 the decision was made
        to withdraw its approval, leaving [ ] as the official symbol for
        this vowel and bringing IPA usage closer to American usage.
        Source: Used as a vowel symbol (but with the value IPA [o]
        (CXS [o]) in Isaac Pitman's 1845 phonotypic alphabet
        (cf. Pitman and St. John 1969 (p. 82)), where it is the
        lower-case print form of a closed script <w>.