Tor Iver Wilhelmsen
I'm curious if anyone has any sense of how difficult (costly) it would be to produce a game using a non-standard card size, versus one of the off-the-shelf sizes? Or is it really not a factor?
The most non-standard card size I know of are in the Pack'O Games series (games like BUS and TAJ) which uses gum-sticker-size cards. Check with the designer/publisher to query about how to deal with manufacturing a custom size.