I have also look been looking into the filtering of information with inputs.conf. But cannot find an example that describes how to set this up.
* Define a filter of type <filtertype> and name it <filtername>.
* Filter types are either 'blacklist' or 'whitelist.'
* A whitelist filter processes all file names that match the regex list.
* A blacklist filter skips all file names that match the regex list.
* The filter name is used in the comma-separated list when defining a file system monitor.
First, the monitor stanzas are URL-like - monitor:// plus the path. Your example had only the two slashes, which would have probably put it relative to $SPLUNK_HOME. And I don't think $SPLUNK_HOME/tom was what you wanted to monitor.
Second, you aren't required to put a filespec in the monitor:// stanza - the *.* is not necessary. If you do put a filespec, however, you shouldn't expect whitelist or blacklist to work. (Internally, Splunk uses whitelist and blacklist to implement the wildcard specification you give)
Third, these are regexes, not globbing-style wildcard expansions. foo* means "f, followed by o, followed by zero or more o" -- so "foo" will match, and so will "fo", and "foooooooooooooooooooo". To make the glob-syle pattern foo* you need to make your regex foo.*. To make the glob-style pattern foo.* you need to make your regex foo\..*
Finally, the filter stanzas in inputs.conf are not used for monitor:// stanzas, but for fschange stanzas. So, you wouldn't use those unless you were setting up fschange.