Direct purchase using PayPal ($100 per license)!
This tool is similar to my Acrobat -- Batch Combine All PDF Files in a Folder script, only it's not a script, it's a more robust stand-alone tool that does the same task but is capable of processing more files quicker and more efficiently.
The tool looks like this:
|The applications' GUI (click to enlarge)|
If you wish to test the tool before purchasing it, a free demo version is available here.
The demo version is limited to processing up to 3 files in up to 3 folders. The full version has no such limits, of course.
For more information about this tool you can contact me directly.