I have always had good luck with the Dell Precision Portable Workstation line.
I've got a Dell Precision M4800 at work - and it does very well. It’s big and chunky though, so I don’t like it due to its size and weight. But it’s very well built. 4 slots for ram, expansion drive, and dockable. It runs CATIA and DPM with no problem. I haven’t tried Solidworks on it, but I assume it would scream.
For CAD work done in my off-time, I purchased a Dell Precision M3800 – and I love it! I made the mistake of upgrading from Windows 7 to Windows 8.1… which is awesome for general use, but Soldiworks hates it. I like this computer because it’s around 14 mm thick, has a touch screen, and is VERY light (a little over 4 lbs), all while having an NVIDIA Quadro graphics card, and a Quad Core CPU.
Prior to these 2 devices, I’ve used Lenovo T and W series workstations for many years. IMHO, Lenovos are better built, and designed more for industry – but I had a few run-ins with their customer support a few months ago that didn’t impress me though.
As for a laptop, you should be fine with anything that has a discrete graphics card. I’ve used Soldiworks on ATI Radeon and NVidia G-Force cards with no problem. I don’t think springing for a “mobile workstation” is essential if you’re on a tight budget. Just make sure you’ve got an i5 or an i7, and a mid to high-level graphics card. I even used Solidworks on a Lenovo IdeaPad with a 2nd generation i3 and integrated graphics for a week. It did fine up until I had an assembly with greater than 20 parts.