Yes, I had considered the same problem. Some of the 06 models I've seen on line had little markings on the seats that looked to be where the isofix would be. I will definitely be aware while looking. We sometimes get the shaft in America and don't get the great innovations and sometimes we come up with them.
I do love my Easy Fix base and had a friend ship it to me from England.
It seemed the smartest and most secure system. Not totally sure it's legal here,as it's only 3 point harness, but I just don't talk about it to anyone. I feel it's one of the safest seats around. But here in the US we have 5 point fever. It has become a popular notion that if your child is not secured with a 5 point harness from birth to age 16 when they are driving, they'll likely die.
I think 5 points are perfect for toddlers and their fiddly little fingers that can get out of anything. But a bit much for my born at 5 lbs baby girl and a going to school child.
Thanks again! S.