It's occasionally bantered about that there are "secret" kata/technique in most every system, including in RyuTe. These mostly amount to the isolated meetings of chosen member's of the association. Though hardly "secret", they are subject to restrictions. Participants are not allowed to discuss the subject matter that is conducted in this groups meetings. Though unknown for certain, it's generally speculated that the general business of the association is being documented for future contingencies.
As far as techniques, I doubt it (no real need). Taika is usually complaining about how nobody ever works on the shown techniques, much less anything new/different.