If you ask me, "SharePoint development laptop" is an oxymoron!
Sure it can be done, but mainly for demo purposes, not serious development where you want fast reloads and not sit and wait for ages after you recycled application pool or did an IISRESET.
I had a pretty decent DELL with loads of RAM and external disk for VMWare/HyperV images, but after i got my dual xeon quad core workstation with SAS disks and 16mb ram i never looked back! The beast is running 2k8 R2 and HyperV on it, and it outperforms any laptop by miles!
The only time i do sharepoint development on a laptop if im stuck on a plane, in a train with slow or no network (we got fast wireless on train in denmark) or for demo purposes.
Else i connect to either ESX or HyperV run on corporate/customer network or my own dev-rig via VPN or Live Mesh (got live mesh on all my hyperv MOSS servers, that rocks!)