n-ary gi is interesting - it may perhaps be a step toward another possible solution to the "extended logical connectives" problem I noted here: https://groups.google.com/forum/#!topic/lojban/Jz6bw4zKn7k
It does however break my definition of {ifle} as {ge ganai me'au bo'a* gi me'au bo'e giga me'au bo'a gi me'au bo'i}, but I prefer {ganai me'au bo'a gi me'au bo'e .ije ga me'au bo'a gi me'au bo'i} over it anyway, and with your n-ary gi, {ge ganai me'au bo'a gi me'au bo'e gi'i giga me'au bo'a gi me'au bo'i} works...
(* Yes, I took bo'V for x1 ~ x5. Additionally, {ka'ei} is a special variant of {ka} that preassigns {bo'V} to its ce'u-variables.)