Here is a Windows command line version PdfSigner with TimeStamp(TSA) support,

Usage pdfsigner InPdf OutPdf Pkcs12KeyStore Pkcs12KeyStorePassword

because It is a demo application, so the TSA server only supports http://tss.pki.gva.es:8318/tsa
If you have interest, please download it here,pdfsigner(4.9M)

Here is a piece of requirement of my customer,

Customer:Is there anyway it can carry on looking at the Open folder once it has processed the initial pdfs?
Me:You want batch readerenable monitor the open folder to automatically convert the pdf, right?
Customer:Yes that is right.
…
Customer:Can I confirm that this is for full automation of the reader enabler application. We would like to be able to select the Open folder and also the Save Folder, also once the pdf’s have been processed can they be moved out of the Open folder? So all that we will be left with is a pdf that has been changed on the Save folder?

And now I have developed my new product, Dirmonitor.
Dirmonitor execute an action when a file is modified, for example, execute command line version readerenable when a file created.

Just finish a little application, PDFResize(aka PDFScale), it is an application that can easily resize/scale your pdf with new size, for example, resize a A4 PDF to A3, or resize a A3 PDF to A4.
The first version will be a command line application.