Just occurred to me, obvious really - IIRC in bb3d I often used an "index array" to complement a list and used this as the "quick-reference" for the n'th element by storing the object/element address. I think my actual usage was a fixed list but indexed differently using several arrays. Usefulness depends on how dynamic your list is, ie, is it fixed length, can it grow but not shrink, etc, but this may be a good compromise for what you want.