My son just turned 12 this weekend and he's also a club soccer player and he's 5'1" and frankly, I expect the same issues with him starting shortly. He currently has a 44cm Fuji. One of the plans I came up with was to buy an inexpensive Nashbar aluminum frame and a 105 groupset and just swap frames as he grows. The frames are pretty inexpensive. I got his Fuji used, so I may just go that route again too.

He's ridden 35 miles with me at times and we're planning on doing a 50 mile ride for Tour of Palm Springs next month.

We have Cardo BK-1 duo intercoms so we can chat while riding (and I can keep tabs on him). if he'd ride as hard as he talks I bet we could cover some serious ground! As it is, average speed is in the 11-12 mph range, peaking at 13 or so when we're on a trail with no interruptions.