Why do you have to have carbon eastons? Or is that to get upto width?
If you could live with 685mm, then EA70s (265g for 31.8mm, 250g for 25.4mm) are around £40 (if you're going lower you won't neccesserily need as much width)
Bontrager do some 710mm aluminium bars for 265g (31.8mm). Might be called rhythms? Bontrager (Race Lite = 31.8mm?) stems are pretty cheap and I think lighter than Thomson X4s (better check that though). Come in a range of rises too
The best way is to check all the manufacturers websites and see what width bars their ranges cover, what weight they come up as and check elsewhere as to how much they'll set you back