I think this looks like a pretty good list. You have enough deep striking and armor simply to keep most people off balance. I also think you have a good balance of speed and a mix of flamer and melta (all twin linked) for horde/mech. The only army that might give you trouble would be a Nidzilla/Daemonzilla army with spammed high toughness multiwould creatures - but then what army does that not give a hard time to?
I wanted to play in the 'ard boyz, as well, but don't think playing (3) 2500 point games the weekend before the waaagh would be a good idea. I think i would be pretty much burnt out after two straight weekends of 40k!