I don't found any thread about that, but I think that would be nice to have for an advance filter .
With some principles and a LLBLGen Template it wouldn't have to be so hard, not only for LLBLGen Team but for anyone.
I started writing a filter like that a few weeks ago, but it only works with LIKE predicates, multiples predicate are only linked by AND operator and is not really reusable by now.
By the way, this kind of advanced filter should be useful.