ALC can give several examples of this, not only in 連れてって:
いつ私たちを湖に連れてってくれるの? When are you going to take us to the lake?
これ、帰りに叔母さんとこ、持ってってちょうだい。Will you take this to your aunt on your way home from school?
The first て should be the one used after 連用形 of verb. But what is the って in the sentence?