Syncing iTunes Libraries Between MBP and MP

If you're willing, you can drop some bucks on Dropbox and try this: http://lifehacker.com/5715126/how-to-sync-itunes-across-all-your-computers-with-dropbox

Or get an external hard drive and make iTunes store all of its music there.

 

Then you have three choices:
Get a second external drive
PAY for Dropbox and get 50GB/100GB (which both aren't sufficient for me lol...)
Buy a NAS

A NAS is especially useful, because it means your data is remote accessible, and you get ginormous storage. You can set your computers to sync all of their data to the NAS, with a program.

 

(Sorry if this isn't "forum etiquette" but I figured I'd ask my question on this thread rather than starting a new one on the exact same topic - if this is known as "hijacking," please forgive me)

Anyway, here is my situation, and I'm wondering if you knowledgeable people can help me out.

I would like to keep my iTunes libraries in sync across my Mac mini and two MacBook Pros. I do not need a SHARING option, for example, where I put all of my data on a network hard drive and point the different iTunes libraries to the same place.

I have a small enough library and desire the portability that I do not mind having copies of all of my media on each device. However, I would like to maintain the library contents and their ratings, play count, etc across all of the devices. Meaning, it's okay that I will have to copy each new mp3 file I add to my iTunes library to each machine (hard drive space, nor time consumption, is not an issue), but is there an automated way of doing this and retaining the desired library data? Basically, I want to be able to add a new album to my iTunes library on my Mac mini and the next time I open up my MBP on my network, I want it to recognize that I've added a new album, copy the album to my MBP, and then update the play counts, ratings, etc for anything that's changed (and vice versa, if I add something to my MBP, I want my Mac mini to recognize and sync). If it can't be done automatically (as soon as the two devices are on the same network), is there a program that will allow me to essentially click a "sync" button, and then the said actions will take place? I should include that I would like for this to work for all media libraries, not just music (ie, movies, tv shows, apps, podcasts, ringtones, etc).

Please let me know if this is even possible or if it doesn't make sense.

Thanks in advance!