You can get a 24-70mm F2.8 from a reputable dealer like Adaroma for a little under $1,900.D7000 bodies can be had for about $$1,000.
As to waiting for a better body I dont think anyone really knows what is coming or when.Like most electronic,s camera bodies become out moded every several years. Remember the D7000 currently has the best APS sensor available.
I would also like to point out the pixel density on a D7000 is almost identical to a D800.Going to a greater density (24M) means that compromises in sensitivity etc will be made.Thats why there is a D3x and reqular D3.
As someone pointed out you can always rent if its just for a cruise.
I upgaded from a D90 to the D7000 after trying it.For me there was a signifant improvement in color rendetion and lo light performance. But if you are using prints of 8X10 the difference may not be worth it to you.