raj009,
the scenario you described is exactly what mine is. i got my H1 after i applied for my citizenship application and no, i do not need to get the H1 stamped again. The H1 i got already has approved *me* the person, not my passport or my country. If my nationality changes my approval for H1 (in most cases - unless my new nationality is of Libya for instance) for the person me is still valid.
re: do i even need a visa/status. as i've said on this forum already, when i inquired about this at niagara on my last trip, the US INS staff on the border told me that with canadian passport i don't need H1 or any other visa to work, i specifically asked about TN and they said not even TN. while posters on this board have clarified that TN is a status but i'm still confused. Going by what the INS staff said, i *need* neither visa (H1) nor status (TN). But posters here say i might need the status of TN. dunno yet, lets see.