The cost of bundles

I watched MinecraftLive and I really love the idea of bundles. I have one concern and that is their cost. In my opinion bundles should be expensive to craft/obtainable as special loot. Here's why:

Take the shulker box: it's a very powerful item, allowing you to transport a lot of resources with you. To get shulker boxes you need to explore the end. You can not automate them (without duping), they are a very end-game item. And that makes sense. Shulkerboxes would be very OP if people could get them cheply.

I think the bundles should also have i relativly high cost. Maybe not as hard to get as shulkerboxes, but they should require some work. Maybe they should be items you can only find in loot chests / dig sites? Then they would be non-renewable while still accessible early game. Maybe they would require some non-renewable/uncommon item. Like a diamond (or amethyst or some other rare cave item) surrounded with rabbit hide (that would be a great way to make players use rabbit hide for something).

The bundles are great, but you really don't want players to have too many of them.