If you are using 1.8 sneaky peek builds, then you could, in the interim, experiment with listing relevant tasks by using the queries:

tasks where estimated minutes is not missing value

and

tasks where estimated minutes ≤ <num>

in the saved queries library of an applescript app (early draft) at http://bit.ly/OFQuery

(This is a tool which also offers a menu of most recently used queries, and helps you write and save your own queries. When a query is run, is shows a list of matching tasks/projects/contexts, and offers you the option of selecting/focusing on some or all of the found items in the front OF window).

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