One timid deletion could become a collector's item (7,7)
I believe the answer is:
limited edition
'a collector's item' is the definition.
(eg a limited edition book might be a collector's i)
'one timid deletion could become' is the wordplay.
'one' becomes 'i' (Roman numeral).
'could become' is an anagram indicator.
'i'+'timid'+'deletion'='itimiddeletion'
'itimiddeletion' anagrammed gives 'LIMITED EDITION'.
(Other definitions for limited edition that I've seen before include "Rare book" , "Small number of copies" , "An issue of a fixed number" .)