It still happens when i just have 1 mod installed with forge. I think its a problem with minecraft itself, the extended block id code was incomplete in 1.2.5, minecraft thinks that only the ids bellow 255 are blocks, everything else is rendered as an item, i'm not sure if 1.3 fixed that.
I have a problem with certain items appearing flat in hand when using an alternate texture pack.
Here is some pics of what happens.
In the pictures i also show some Minecraft ores to make it clear which texture pack is being used.
1st pic - Just shows you what mods i have in the jar file.
http://db.tt/DiHgS5Hi
2nd pic - shows the config file for the mod item (iron chests mod) with an ID of 2430
http://db.tt/8dvtn4lZ
3nd pic - Shows what texture pack i have selected (Faithful 32)
http://db.tt/tOvCqyEL
4rd pic - Shows the name of the item selected and its item ID
http://db.tt/2YRv6Gsi
5th pic - shows the item (Iron Chest) Placed on the ground and in hand. Note how the item is flat in hand.
http://db.tt/a5JgrAwG
6th pic - Shows the Default texture pack has been selected
http://db.tt/sRCHAUqK
7th pic - Shows the name of the selected item and its item ID
http://db.tt/gyV87bYg
8th pic - Shows the shows the item (Iron Chest) Placed on the ground and in hand. Note how the item is how it should be.
http://db.tt/zeefdjaU
This is just one example. It also happens to any item that is over ID 256.
Aswell as the Faithful 32x32 texture pack this happens with the Shax 128x128 texture pack.
I have also posted this on the Faithful topic on the minecraft forums.
Any help would be much appreciated.
Thanks