Sorry about the images, figured it out, Images are in order described above:
I've been putting a lot of thought into customs for this game almost from the start, and more recently since the game has reached it's end, I've been looking at ways to field the models that had rules but had never been created (This particular one is something I thought of early on, but refrained from doing it because I had hoped we would eventually see an official model.)
Since it was a cost effective way to get some of the stock models, I opted to purchase several of the starter set of Alien vs Predator, and while I have kept all of the Aliens and Marines, I ended up tossing three sets of the Predators into a box for possible future customs. I pulled a couple of those out for this particular kitbash.
This first image is of a couple of Purple Shark miniatures from the Mutant Chronicle game. The rider comes as part of the bike, so they had to be cut away, but it wasn't too hard to do. I took an image of both of them, one with rider, one without to start
The second image is of the first predator I opted to use for this, and of the three in the starter this one is hands down the best one for the job though with a little bit of work any of them could work. I cut him in half at the waist, and the hand broke off on it's own, but I had planned to remove it anyway so I didn't mind.
Now, this particular predator was a little too bulky to fit the hips of the biker, so I shaved his back a little bit. I went higher than I should have, but it should be easy to touch up.
This is with the torso attached. Being that the models are both done in 32mm, the match is pretty good. Just a little bit of putty should fill the gap with little trouble.
The bikes come in a two pack and I did a second one with the disk Predator. The arm didn't match up to the hand on the bike handles very well, but that could be handled with a repose of the arm (Maybe do something to bend the elbow a little for the best results).
I hope people fine this useful.