Hash generator
I would see that feature in the Hashcat-utils. It would be useful for both making hash files to test the Hashcat's products with them and sometimes to know what hash format the Hashcat product want to "see". For example, if you don't know how the SSHA1 hash has to look like, you use the tool to generate a couple of test hashes with passwords that you know and look at the hashes generated.

The tool would be a command line one, of course. Taking a password file as input, using the same -m switch has the Hashcat product. For the salt and/or the username, they could be provided in the password file (passwordConfusedalt or password:username) OR in the command line if it's a unique one applied to all passwords. A -o switch to send the output to. A bonus would be also to be able to select between an output as Hash only or Hash:password or Hash:Salt/UserTongueassword.
I do have a test-tool for oclHashcat-plus that covers nearly all the algorithms. Its written in perl plus you need a lot of additional Perl-Modules. Is that ok?
Hi mastercracker

It seems as if atom has already got something worked out for you but you can also use ULM to convert passwords lists into hash lists.
+1 for hashgen tool