FINNISH:epäjärjestelmällistyttämättömyydellänsäköhänkään =48 letters
Translation goes something like this:
[Asking while expressing double (serious) doubt] not even with his/her most disorganization causing way
Or replace disorganization with methodicalness breaking
Not spot on, but can't get it any better.
BTW: Base word is järjestelmällisyys (methodicalness) (or järjestelmä (system) or järjestys (order) depending how much you want to backtrack) rest are pre- and postfixes.

BTW2: nearly impossible to use in sentence.
BTW3: Probably too many pre- and postfixes to be accepted in GBWR, it used to be there though in bit shorter form-
BTW4: Sweden had in GBWR combination word of 120+ letters, but Finnish could probably beat that.
