And is it possible to put idioms together, like this? 'Выдумаете порох после дождичка в четверг', this would as sarcasm. From the negative 'пороху не выдумает'.
Good question. I would personally not do it, as I think the idioms are something very stable. If I would say something like: "That is set in stone once in a blue moon," would that sound good in English?