Are there any sites which document the various weapon enhancements, such as 'of readiness' or 'of the swift' ?
I can't find anything anywhere???

You can use NxModsuite to read the modifier.bin file.

Here is modifier.bin opened in that suite: http://pastebin.com/Z1ZjQcLX

hmmm... well, in truth, that doesn't really answer any questions at all...

For example, I'd like to know specifically what the Readiness effect does...
This information is singularly uninformative about that question... all it tells me is that there are 4 levels of ReadinessEffect, but nothing appears to ever actually say what that does...

I've seen one or two people speculate on what it might be, by parsing the words - something which I could certainly guess at as well - but I was really hoping that someone, somewhere, at some point, actually had knowledge of what the program *actually* did with this effect... so far, I've never seen anything get even close to discussing it.

I have the Nox strategy guide which has a full list. For Readiness, it says:
Enchantment - Level - Color - Effect - Weapon Type
Readiness - Level 1 Readiness - Red - Quick Reload - Bows
Swiftness - Level 2 Readiness - Red - Quick Reload - Bows
Reaction - Level 3 Readiness - Red - Quick Reload - Bows
Quickening - Level 4 Readiness - Red - Quick Reload - Bows