Can "东西" refer to a person instead of thing?
don't use 東西 for a person, it is for angry only and negative assessment. 他也不是個什么好東西。(he is not a good man). when you translate such statement into Chinese, you can just make sure appending a '的' at end. In Chinese '的' following a verb can be used for 'what xxx (a pronoun) yyyy (a verb)'. so 我找到了梦寐以求的。