I don't believe that it is so difficult. I am only speaking of having a webGUI in Spanish. Only that.
We have collaborated in other translations to Spanish of other projects. It is not so difficult. I place you a localization example to Spanish carried out by us: http://www.insidepro.com
It is based it on placing texts like variables.
Then, a called file exists SPANISH.LNG that contains the equivalent of each variable in Spanish. Of course, there is a called file ENGLISH.LNG with all the texts in English. And so forth.
I am willing to pay 200 dollars for this work.
I believe that Pfsense in several languages would be fantastic, and the best firewall in the whole market. With this system, you would find people that wanted to translate to their language the texts. It is possible that in little time you were able to have Pfsense in 10 or more languages. Something incredible.
It is more complicated for the development, but Pfsense it will win an international prestige that other commercial firewalls doesn't have.CARLOS MESA