How is that possible, when many GC games are over 1.4 GB (the max size of mini-DVDs)? The only larger versions of that size DVD (8cm) are double-sided, which obviously wouldn't work with a game not meant to be on a double-sided disc.
The Viper case mod increases the actual bay size of the GC, so you can insert and run full sized DVD-R media. I'm hoping this Wii modchip lets you just play games off a full DVD-R.
Actually only a few GC games are more than 1.4GB and those are all 2 disc games - there are no retail GC games on dual layer DVDs. The only reason the case mods exist are because full sized media is cheaper than 8cm media.
Also the Wiinja mod chip doesn't say anything about playing GC games yet, besides for all we know there may be physical lock/switch in the Wii to distinguish between Wii and GC games by size of disc, e.g. like how the GBA has a switch inside the cart slot to boot into GB mode when pressed by the extra plastic moulding on the base of the GB/GBC carts.
=)