Well if it's any help, I've just seen an ad from a company selling upgrade parts for the LifeBook B3010D, and amongst those parts are two new IDE hard drives 120GB & 160GB capacity which seems quite plausible, although it doesn't say that's as high as you can go. But at least that's a step in the right direction as far as your question is concerned, so I hope it helps.
The ad is from a US-based company if you want to see it for yourself:
http://www.bixnet.com/flbb3010d.html
As you'll see, both drives are out of stock but it should still help you nevertheless.