Have at it! ICANN has formally confirmed that the gTLD .internal will never be delegated.
I still recommend using something you own, but if you're not up to that, so be it. ;)
Edit: sure, go ahead and s/own/rent/ if you feel that way inclined. ;)
Domain Incite - Domain Name Industry News, Analysis & Opinion
Itβs official, .internal is blocked forever - Domain Incite
ICANN has formally confirmed that the gTLD .internal will never be delegated. Its board of directors resolved earlier this week that it "reserves ....