Theoretically you should be able to hook an Endertank up to a RC(or some other large tank) tank with BC pipes and gate conditionals so that whenever the Endertank is full fluid it drawn from the endertank to the RC tank and whenever the ET if empty fluid is pumped the other way. You could then bring a matching endertank with you and have a quite large "portable" storage with you. Something I always speculated about setting up since 1.4.7 but never really had the reason to