A mini lop is huge compared to a himalayan and has a much larger/rounder body shape and a huge head too. I'd be worried about the doe having stuck kits. That would require emergency vet care, possibly surgery, and can be life threatening for mom and kits.
Why would you want to anyway, even if it was safe? You'd probably end up with a generic mutt bunny, uppy eared and no Himalayan (siamese-type) color points. I have nearly a dozen of those at the shelter here. Want some? There'll be another dozen to replace them soon.
What do you want the babies for? I'm all for breeding for show but ifyou just want cute babies it's not a good idea. It will be harder to find homes for mixed breed babies (trust me on that too!) and you can't show them at all unless the local 4H group has a pet/mixed breed class. If you really justwant cute babies to raise talk to local shelters and rescue groups. I've had two litters (one still here at them moment) and a pair of orphan babies this summer.
Edit: I'm not trying to be harsh, we're just having lots of shelters overflow with rabbits at the moment and I'm fostering babies for my local Humane Society right now... and there's no room for them at the shelter when they get bigger. I'm all for breeding for a set purpose, such as ARBA/4H shows or working on a genotype.