Via my California Corp HQ, I have a Cingular account with BBerry 8700 (great Email device!) for intl data roaming. Costs USD$64/month with unlimited WW data roaming (Email & Web).

Sadly, Cingular's voice plans suck for Canada. AT&T Wireless used to have a voice plan similar to Bell's (Unlimited NA Roaming for a flat monthly fee), but Cingular is not carrying it over.

So I carry my Cingular BBerry for data and Bell Razr (almost perfect voice device) for voice in NA with unlimited roaming. Not exactly unified single device harmony, but it's functional in a "best of breed" sort of way.

One intriguing possibility I haven't investigated yet is Google talk for my BBerry. Every time I try to click on the link using my 8700, the page doesn't load. Wonder if that's because Cingular (or Bell for that matter) fears they may never see another voice dime from me if that VOIP technology over GSM/EDGE actually works