I guess it depends on the yields they think they could get, but it would be I think unprecedented for a LCC to take on such routes. Was trying to think of the longest LCC route, globally (with regular public transport operations). The longest I could think of was ZipAir, Tokyo to Houston at ~6640 miles. Not sure if there are others*? But if Jetstar would stretch to LAX or LAS it would be 7500 and 7700 miles respectively, that's a fair bit further than NRT-IAH. PER-CPT might work though, it's similar in range to MEL-HNL
* Then looking at Scoot , Singapore to Vienna and Athens (~6000 and 5600 miles), and ZipAir again to LAX/SFO/SJC 5100-5400). MEL-HNL is 5500 miles.