Tablet PC advice?

I'm looking to buy a tablet PC for work. The models I've seen good reviews of are Lenovo Thinkpad, HP Pavilion, and Fujitsu LifeBook. What I want in one, in order of priority is as follows.

1. Dual-core processor


2. High RAM


3. Windows XP


4. Sturdy and reliable


5. Lightweight


6. 5 hour battery life


7. Large hard drive

Specifically I will be using the tablet to give a presentation in PowerPoint, which I'll be annotating with the stylus, while running Camtasia (screencasting software, which records what's presented on the screen along with an audio track). I will then need to render the Camtasia recording and post it online. Camtasia's a memory-hog, hence the first three items on my list.

I have a $3,000 budget limit, and the money's not mine, so I'm looking for the best I can get.

Got any advice for me, or links to reviews?