This topic seemed to fit best with what i'm asking, although it's not quite a breeding question!

We adopted our cat, Teegan, from the pound when she was about 4 months old. She was rather large for a cat that age and we were assuming that the pound was lying to us about her age just so that they could get rid of her. (she had lived there since she was about 4 weeks old, and we originally asked for a kitten when we went in) We didn't mind however, we fell in love with her instantly.
She has many, many quirky and humorous traits that I've never seen in other cats before. For example: she eats and drinks using her paws, is rather clumsy when it comes to climbing/jumping/any kind of vertical activity, very affectionate (although she hates to be held) and easygoing, shes quite smart and comes when called like a dog... shes just very dog-like in all ways, and she chirps rather than meows, just to name a few.
She is almost 10 months now, going by what the pound told us and she is the size of a larger full grown cat and still noticeably growing.

Recently there was a cat show in our city, and I noticed the picture of the best overall prize winning cat in the paper because it was nearly identical to our Teegan. After finding out the name of breed (Maine Coon) I did some research and she fits the physical traits of the breed 100%, right down to the linx tips, tufts in the bottom of her paws and the extremely soft fur, with the exception of the size thus far, seeing as we don't know her exact age. She also fits the majority of the Maine Coon's trademark mannerisms.

Now, I'm 90% convinced that she is Maine Coon, maybe not full but theres definately some in there! I'm wondering however if there's anyway to distinctly guestimate what age she might be, or how big she might get. And also, are there any die-hard, tell-tale signs that might give me that last 10% reassurance?

This is a link to an album I have on face book with photos of Teegan for visual reference.
Most of the pictures were taken a week after we brought her home.
http://www.new.facebook.com/album.php?aid=34319&l=c6524&id=554396684

Not much info I can give to tell for 100% what the breed is. Maine coons sometimes have extra toes from what i was reading, however this feature has been breed out of them for the most part because I guess if they have extra toes they are not allowed in cat shows as pure breeds. However I can not remember did you think you cat was extra large? I was pretty sure this was normal so I looked it up and did find one reference to their size pretty quick and that said "A full-grown female typically weighs between 9-12 pounds and males tend to be in the 13 to 18 pound range." So prepare for a large cat.

Sounds like you have a very unique cat with the things you were saying. I had a cat once also who always dipped her paw into the water bowl and then licked the water off her paw.

I am however very surprised that this cat would have been at the pound since she was 4 weeks old. I figure that kittens would be the first to leave and go home with people. But I suppose anything is possible.

Sorry I could not supply much information but it sounds like you have done a great deal of research yourself.

Oh and welcome to the site, hope to see you around often.