Maybe not the answer you're hoping for, but if some part of you code need heavy work on collections (searching, sorting, filtering, transformations, analysis) you may take in consideration to write some classes in Clojure or Scala.
Because of their functional nature, working with collections is what they're best at. I don't have much experience with Scala, but with Clojure you'd probably find a more powerful Linq at your fingertips and once compiled, the classes you'd produce would integrate seamlessy with the rest of the code base.
