How can I quickly open a text file from the iPhone's home screen? Just like you can save a URL from safari to the iPhone home screen, I want to put a .txt-file on my iPhone homescreen. 

I use PlainText to store my files, but sometimes search is too slow. For my heavy used documents, I'd like to store them on my home screen.

I'm prepared to jailbreak if needed.
If you jailbreak, you can install file:// in MobileSafari from Cydia. this would allow you to place text files somewhere in your filesystem (using iFile, also available from cydia) and access them from MobileSafari. for example, a file called text.txt in the root / directory would be file:///text.txt.

You can just open these files in MobileSafari and then add them to your home screen.