Googling the subject, I came across this beauty:
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It looks like what I imagined Space Cowboy described a few years back, re. shortening the rod in a French press. (Except double-wall borosilicate glass.)
Googling some more, Jing Tea Shop sells 'em.
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; the 600mL "tea-iere". No affiliation, though I might buy one someday.)N.