Heh, seems like lots of people have written solutions for this sort of problem. Here's the one I wrote: Re: seeking in hash data structure (can handle a list of strings being parsed into a single hash structure, and includes a "trace" sub to look for a given hash key anywhere in the structure).

It's the same sort of process that's used in building "Trie" trees over a list of words (to analyze "prefix patterns" by building this sort of hash from the letters that spell the words), and there are a few different CPAN solutions for that.