Public Service Announcement: 150 planar shards from the subterrane can be traded for a large collectables bag (80 items, stack size 1000). Huge collectables bags are available from the DDO store (waiting for a sale is recommended), 200 items, stack size 100.
The planar shards are bound but the large bags are not bound at all and can be sold and traded between players. I don't think any of my non-bank toons are using medium bags anymore. (I know none are using small bags.)