I have never done cross processing so I will follow this thread with interest. In fact as its warmer in the house than the workshop I think I'll spend some time tomorrow on a net search to see if that turns out any usefull info.
E6 (transparency) processed in C41 (colour neg) I have heard of but not the other way round. And therein may lay a processing problem if you go the C41 process in E6 route. To avoid overcontamination of a processors chemicals they need to be doing a lot of E6 to allow for processing a single C41. As Most film processors are doing more in colour neg then it would be easier to slot in one E6 film without screwing up the chemicals.
Also if its C41 being processed in E6 I would expect a longer than standard development time rather than exposing the film for push process.
There you go ....... committed myself to get involved now
Don