EnumerableSplit.cs

static class EnumEx
    {
        public static IEnumerable<IEnumerable<T>> Split<T>(this IEnumerable<T> list, int maxItemsByPart)
        {
            return SplitImpl(list, maxItemsByPart, 0, new List<IEnumerable<T>>());
        }

        public static IEnumerable<IEnumerable<T>> SplitImpl<T>(
            IEnumerable<T> list, 
            int maxItemsByPart, 
            int itensSoFar,
            List<IEnumerable<T>> accumulator)
        {
            var listSize = list.Count();

            if (listSize <= itensSoFar) return accumulator;
            else
            {
                var maxInIteration = GetMaxInIteration(listSize, maxItemsByPart, itensSoFar);
                accumulator.Add(list.Skip(itensSoFar).Take(maxInIteration));

                return SplitImpl(
                    list,
                    maxInIteration,
                    itensSoFar + maxInIteration,
                    accumulator);
            }
        }

        public static int GetMaxInIteration(int listSize, int maxByPart, int itensSoFar)
        {
            var parts = listSize / maxByPart + (listSize % maxByPart > 0 ? 1 : 0);
            var itemsByPart = listSize / parts;
            var restItems = listSize % parts;

            return itemsByPart + (restItems > 0 ? 1 : 0);
        }
    }