That is definately true, no US airline will sponsor non-residents. I made the assumption (my mistake) that Tim has the right to work in the US either by citizenship or resident alien, sorry. Definately should consider that as a local pilot, you're missing out on a good chunk of change (unless the local union negotiate housing/edu allowances for local pilots too).
With the looming (some say it's here) US recession, you'll probably see a slow down in the US aviation market in 2008/09. Never bolds well for current pilots, let alone low hour CPLs looking to get hired. Perhaps the pay difference might be worth it! At the very least, having the option to go through the CXCPP can never hurt.
I'm going through the same dilemma, and there's no easy answer.
Good luck to all!