What would change material do on an ice box? I can think of a few different options:
1. Ice is the secondary material of the ice box, and change material affects the primary material. When the ice box melts you're left with a lump/stone/stick of the primary material.
2. An ice box is a new item and ice is the primary material, but an ice box not made of ice doesn't provide any resistance to spoilage.
3. An ice box is a strongbox or chest made of ice. The name changes when the container is made of ice in the same way that plate mails are change name when made of flexible material.
In any case, preventing spoilage probably wouldn't be too difficult - just make them work the same way as shop floors. However, making ice melt would be a totally new feature. At the moment ice is just another mineral. Should ice objects melt piece by piece or all at once? How much should the melting process be accelerated by explosions? What happens if a bottle is full of ice?

Only if the icebox magically unspoils items. Zolku's bananas are cheap because they're a few ticks away from having flies, not because Zolku sells at low prices.

Survivability is one factor in mazes, frustration is another.

Are you using a fresh download of 0.50.7?

The problem with mazes, especially large mazes, is backtracking. If the maze has tree topology then a large portion of tiles need to be traversed twice. That's not so bad if you can use the 'g'o command to automove through corridors, but IVAN's automove stops at corners and on items.

Two approaches to making automovement smarter in this kind of situation are Angband's run command and Crawl's autoexplore command.

Angband's run command is invoked like in IVAN - you press . then a direction and it keeps moving in that direction. If you're in a corridor, it follows the turns in the corridor without asking for confirmation. It stops when the path forks (in quite a broad sense) or when a game event interrupts you (interruptions are configurable).

Angband's system is also augmented by the squelch system, which lets the player tell the game to ignore specific items, types of items, or general items of different levels of quality. Ignored items are automatically dropped, don't show up on the floor, and (crucially) don't interrupt you when running. In IVAN this would help greatly when running through mazes filled with inedible corpses and low-quality equipment.

Crawl's autoexplore command automatically guides the player to unexplored accessible areas, taking the shortest possible route. Basic implementation is pretty simple with Dijkstra maps, but Crawl may provide some additional features (like stopping on new item detextion). Darren Grey doesn't like autoexplore. Or doesn't like games where autoexplore is a useful feature, because choosing which area to explore in a procedural map should have strategic/tactical consequences.

I think it would be best to implement one of these solutions before making mazes in IVAN larger than they currently are.

Speaking of being bitten by canines... Rabies for president in 0508?

Raising END to 1000 in wizmode and getting instakilled by a critical hit while naked makes it pretty clear that AV provides some kind of protection far greater than just being subtracted from damage values. :>

This is kind of what I was alluding to on the last page; damage reduction for most damage types is based on AV, which is material strength times the item's strength ratio. However, for sound damage and blunt weapons it would physically make more sense for damage reduction to be based on how much energy the item absorbs, and the best approximation IVAN can make to that would come from item volume (or thickness, which could be approximated using bodypart volume) and material flexibility.

However, if a system like this was implemented, blunt force would have to be separated from sharp implements, and equipment would end up with two armour values, which... bleh.

Also, strong dense inflexible armour could still help with sound damage reduction. Assuming the armour is rigidly attached to the body (lolno) The additional volume from the armour causes slightly more energy to be transferred to the character. The additional mass from the armour reduces the change in the character's velocity from that energy (which would be proportional to the amplitude of the sound passing through the character's body). If the armour is dense, the latter effect should be dominant.

Of course, this ia a world where standing next to an enner beast poses great health risks but being one is fine. Probably it should just work however is most fun.

What are the materials people think should resist sound damage? Is it possible to classify them simply using already existing properties (probably strength and flexibility) rather than adding a new flag and setting it on individual materials?
For instance, flexibility > 4, or flexibility*strength > 150?

Weeping crystal blades don't break from acid due to material properties, but try dipping other types of weeping blades in bottles of sulphuric acid.