Hey, I was just googling for a siamese/manx add because we lost our 8 year old siamese/manx (Gregory) around this past Easter.. I wasn't aware that they were an actual mutation that was bred on purpose. Mine was actually born from a mother that was a longhair black cat stray! LOL! She was my friend's cat she took in, and didn't know who the father was. And I took in one of the kittens, they were all siamese and only one had a tail. Mine had like a stub that kind of hooked at the end. Anyway, it's so weird you said yours was really light as a kitten and got darker, mine did the SAME THING.. He was snow white at first with the dark brown/black points, and every year he would get darker and darker, and he was just beautiful.. I think someone stole him. We did not like him going outside, but he loved it. And we live next to an apartment complex. So I am just hoping someone did take him and is taking care of him and loving him and not dead somewhere.. Before we had our son who is 4 1/2 now (Ian), Gregory was like our son, we even had his pictures done professionally.. I have them somewhere I don't know why I have never scanned them, it was so long ago, but anyway, he was super super super smart. I don't know if it's the manx or the siamese, but he was brilliant. And i have had a lot of cats in my life.. Growing up at my moms we were like a shelter for cats, people would dump them at our house, and our yard would be full of them.. But anyway, he was like our son for those first few years, so I actually was just joking with him and started doing the 1-2-3 method, and 3 gets a spanking.. (never spanked him, but for kids, that's what they get.. lol).. And THAT CAT NEVER LET ME GET TO 3 BEFORE HE STOPPED DOING WHATEVER IT WAS THAT HE WAS DOING AND HAULED TATER!! LOL!!!! He was very smart like that. And if he had one quarter of his food gone, or his water was not full and his litter box was not up to par, I am not kidding, he would gripe at me, like come to me and start meowing and would not stop until I got up, and if I did not go straight to his needs, he would grab at each foot with each step I took!! And we had a recliner right by our front door for a few years and if I would act like I was going outside, he would run right up the recliner and grab at me!! LOL!!!! He was awesome.. We really miss him.. I am so glad to see that there are other people out there that have them and love them like we loved ours.. Is your cat doing anything like that? It was like Gregory had a personality like no other cat I have ever had, and the only one that ever came close was a cat that had extra toes, I think they are called polydactyl.. I have had two cats like that, and they are brilliant too.. I have been looking for another siamese manx, and I found a woman who breeds these AMAZING CATS.. They have several mutations, and some of them look like white tigers, they get HUGE like bob cats, they have bent ears like bob cats, and bob tails, some have the poly-dactyl feet, just a bunch of neat differences, that I have not found on any other cat.. And they are all colors, they have siamese too, which is why I am really thinking of getting one, but they are not that cheap either.. They start at $300, but to have them shipped is about $300 too, so I am looking to see if I can find another somewhere cheaper, but they are dolls, all of them.. They have some that are white with stripes, JUST LIKE WHITE TIGERS!! I have never ever seen normal cats look like that.. Just beautiful.. Anyway.. Sorry for such a long story here, I am just excited to see, on my first google search, someone who has a cat that sounds just like my Gregory. I am not sure how to post pictures, but my Greg looks JUST LIKE THE PETLUVSFORLIFE PICTURE, I MEAN THEY COULD BE TWINS!!!! BTW here is the link to those kittens I was telling you about, they are beautiful, if anyone wanted to see what they look like.. If I can find out how to post a picture on here, I will post one, I just signed up to reply to your post.. lol.. http://www.rottins.net/kittens.html