Any tips on making or buying pinholes suitable for reasonably detailed 4x5 (or even 8x10) images? I'm going to just pinprick a hole in some tinfoil and see what I get (whenever I can find the time to get out for some shooting, probably on christmas vacation) but in the event it's not sharp enough (I've seen nice detailed pinhole images from large format before) I'd like to know where to go.

I've given up on finding that cheap 65mm bargain any time soon (I maxed out at $500 on the last one to end on ebay today) so I figure a pinhole is the next best way to get ultrawide. Hell, I like the semi-soft look of a well made pinhole anyway.