I think, it would be best to have a seperate gpx2 section on the board, and a seperate "Latest Posts" on the front page to be able to see if it`s a gp32 related post or a gpx2 related post.
I think the board will get too chaotic once the gpx2 is out - and if the board isn`t seperated into a gp32 and gpx2 section, it will get really hard to keep track of what is happening on the gp32 (remember, not everyone is going to buy a gpx2!). The few gp32 related topics at that time will be drowned by a flood of gpx2 threads...