For illustrative purposes in the examples below, I'll use oo instead of my usual u to transliterate the shuruq and qubutz. Also, for convenience, I'll use the term shuruq to include both shuruq and qubutz.
I can believe your assertion for words whose "shuruq syllable" is closed and unaccented (e.g., shoolxan, moor'ato, and goonov goonavti) or closed and forms the entire word (e.g., mool and shoov), i.e., I can believe that you (and some others) pronounce the "oo" in these words like foot rather than like moon, although I personally use the "oo" sound as in moon even for these words. And (unlike you) that's also what I've heard from most other Ashkenazim.
However, the "foot" pronunciation sounds completely foreign and off base to me in all other cases, i.e., in words where the "shuruq syllable" is open or accented (in words with more than one syllable) or both (even in words with only one syllable). Here are some examples.
OPEN: shoolei, t"moora, g"oola, oolay
ACCENTED (in words with more than one syllable): katoov, ashoor, vayit"noom
BOTH: m"ooma, loo, sham"ru / kat"vu / akh"lu and all verbs of that form
Zev, do you use the "foot" pronunciation in any of these words? I truly can't imagine that pronunciation in any such cases, but I'll certainly take your word for this if you can confirm it. Again, I personally use the "moon" pronunciation for every shuruq --- even the ones in the "I can believe" categories delineated above. That's why I (and most other speakers whom I've heard) have to resort to galoo-ee and tzivoo-ee because it's impossible to pronounce a pure "y" after "oo" as in moon.
Art