The City of Vancouver is currently considering a proposal for Whitecaps Waterfront Stadium, a new stadium to be built over the railway tracks east of Waterfront Station on Burrard Inlet. This 15,000 seat stadium would replace Swangard Stadium as the home field for the USL's Vancouver Whitecaps, with a proposed opening date in 2010. There is a fair degree of controversy with regards to this location — Wikipedia
When I wrote about Vancouver as a possible MLS expansion site, I wasn't aware of the proposal above. With an expanded capacity of up to 30,000, this could be an ideal MLS stadium. It might require promotion of the whitecaps though, something I'm not sure the MLS is willing to consider.