On 26 Aug 2013, at 17:14, Rob McBroom wrote:

[…] I see “Completion List” as an option […] Is this one of those things that hasn’t been implemented yet?

Correct, not implemented.

But you can set the output format to snippet and then create a snippet using this syntax: ${1|first,second,…,last|}.

An example is Header Completion in the C bundle which can be used on a line like (⌥⎋):

#include <s‸>

It will show a completion menu with “type to narrow” for the headers starting with ‘s’.