I know you said top punches, which are fairly rare being the size of Canada casting population. But if you not against lee push through there is a fellow named the Chemist on here who has a connection with lee products. Lastly there is another fellow in Saskatchewan who makes custom molds, you can always ask him to make you one, he seems to be fairly good with machine tools, not to sure but he quoted me $40 for a custom push through which was great for me.
Boomers Moulds