[quote name='goldengraham']Are you sure these are safe enough for say, N64 and GBA boxes? I really wouldn't want to send it out and turn out to be crushed in when the trader gets it.[/quote]
To be honest, any paper box would probably be slightly crushed or bruised during the shipping process. The padded envelopes are better suited for hard cases (DVDs, CDs, etc), so if you're going for box preservation, it's better to use small cardboard boxes for shipping.