While I was working on some item_data reconstruction(A Paid Source requested to me..) I discovered that we can create ItemID with greater than 32k ID. (Atleast on 2013-08-07,Since I use this mostly, I tested it with this client.), so maybe as kRO has reached almost 30k, they already increased itemid range...
Some of the testings: http://imgur.com/zKGwMFZ
Also I tried to make different items like equipable, usable, and I was able to wear and use them....
We would need to modify some mysql tables and change some "short" type(in source)...
Atleast I tested until 65535 , So maybe client is restricting ID > 65535 now?(Since Item Failed to create when tried with ID>65535).
So my suggestion is to change short types and mysql tables, and make itemdb support to 65535 by default...