I would give my left ... for a 5400 or 7200 hard drive for my x40. Will these drives come out any time soon?

I wouldn't hold your breath on these. These drives are gonna be used in a lot of personal electronics, which don't probably don't need high transfer rates.

With that said, the HD speed on my x40 is the bottleneck in an otherwise speedy system.

I briefly had a Sony U50 which also uses a 1.8 in drive (although I think from Toshiba) and it was just as slow. Installing XP or long disk operations take about 2x as long as a normal laptop 5400 rpm drive...

I would keep an eye on Newegg.com, they sell the same hitachi drives, if they speed up the drives, I bet newegg would eventually carry them.

I'm trying to decide between the x40 and x31. I'll likely get the x31 due to the lack of a 5400 or 7200 drive for the x40. I fear stinkypete's analysis is correct, and that we'll see higher capacity drives, such as the recently announced 1.8" 60gb drive, but it'll be a long while until there is a fast 1.8"