I've been thinking more about the roof situation.
I had mentioned
above that I really liked the design of the roof on the proposed Halifax CWG stadium. I like the way it arches over the stands, and looks to be partially supported by those massive towers. Something like that could work very well with your proposed design fenwick, as your stands partially wrap around the ends. The playing surface would be uncovered, but you mentioned at one point the possibility of a temporary covering (fabric maybe) over the playing field, which could easily be installed or removed. Perhaps it could be partially suspended from those large support towers on the CWG stadium design? I'm thinking something similar to the Montreal Olympic Stadium roof, only y'know.. not a huge disaster.
I should actually explain that a bit..when I say similar to the Olympic Stadium roof, I don't mean some half-baked retract-it-into-the-tower scheme, I just mean a fabric roof that is supported by cables from towers. Would still have to be manually installed or removed.