[1.7.10] Changing Vanilla Chests

I'm working on something for a friend which involves a number of vanilla tweaks. Most of these are quite simple and just involve editing drops and whatnot but this one has got me stumped.

Changing the inventory size of vanilla chests to 9 - Making a block to do this is pretty easy, extend TileEntityChest, change inventory size to 9, extend BlockChest, point it at the new Tile Entity. However this is the first time I've tried overriding a vanilla class since 1.6.4 when you could just set the ID the same and getting this SmallChest to register as "minecraft:chest" in 1.7.10 is giving me trouble. The slight wrinkle is that I want the chest to behave completely normally for the purposes of crafting etc, so I am wary about editing every recipe that contains a chest to instead contain a small chest so I think overriding the vanilla chest is the best option (but please feel free to correct me)

Possible solutions I've come up with so far, slight escalation in complexity:

[*]When the player tries to place a Chest, instead places a SmallChest, SmallChest drops a vanilla chest when broken

[*]ASM to allow editing of Blocks

While the first option works, it's not particularly neat and could probably be bypassed by getting some sort of block placer to place a chest so I don't particularly want to do it, the second is, well... icky. Would really appreciate your thoughts on the topic, any possible solutions to this issue that you can offer would be great.

P.S. methods that don't work:

public static Block registerBlock(Block block, Class<? extends ItemBlock> itemclass, String name, String modId, Object... itemCtorArgs) - deprecated

public static void addAlias(String alias, String forName, GameRegistry.Type type) - not yet implemented