I like the idea of doing iron crosses, but my gym doesn't have the facilities. We do have a variety of other ropes and such though, which they have announced they will be expanding soon - gyms in my area seem to be pushing these new "whole body" sorts of exercises. I forget the term they use but it involves stuff like doing push-ups with your hands or feet in free-hanging stirrups, I guess to increase core strength. Doesn't seem like a bad idea.
Ah... Sounds like my kind of gym. I've been to gyms for professional gymnasts, and the 'usual' gyms with weights / weighted machines, but I haven't encountered any which encompasses both aspects of strength training (bodyweight exercises vs weight-lifting exercises). Training with ropes are great as they train your grip like few other tools can, and it's certainly possible to do an iron-cross on 2 ropes. If the stirrups are positioned high enough, maybe they could be used as makeshift rings?
I usually alternate between free-hanging bodyweight exercises and lifting weights. IMHO, they complement each other well.