First, thanks for a great and honest product. I'm surprised Apple hasn't hired you folks yet ;-)
I was wondering if the usual "File Action" shortcut [⌥・⌘ ・\] could be used to place something in the File Buffer? You'll recall that that only way presently to add something to the buffer is by [⌥・ ↑], which is great... IF you're browsing from within Alfred. If you're traversing multiple folders in Finder, this would be a tremendous time-saver.
As an aside, would you be amenable to the idea of making available some sort of programmer's API? I'd be happy to code this up myself