While scouring Yahoo Japan Auctions, I found out that there is a set of Tri. related bromide cards.
Unfortunately the only card with Yamato also features Sora, but bromide cards are usually nice, oversized cards. It appears these could only be obtained via lottery prize through the Marui Annex (?). I'm not familiar enough with everything to explain what that means, but I assume that it's one of the theatres showing Tri / Tri cafes. It looks like if you purchased 3000 (points? yen?) worth of some kinda card at the shop, you were entered to win them.