Interesting this one. Has been discussed in the VS rumourmill. I did hear some staff from RG mention 2008. However right now we couldnt handle it at LHR its at saturation point already.
Personally I would love us to do it. It would be sooo virgin. Yes i did travel out there in May and the loads were very high on BA on the way back ended up being kicked off in GRU. Managed to scrape the last seats on the LH service to FRA. Economy in Rio is supposed to be on the up and up im sure it would be profitable.
Brgds
SJD