It probably is a pipe-dream to get Team Fortress 2 on a smartphone (and a pain to play so its better left that way) but TF2 on a laptop is an everyday occurrence now. The specs that came out for the Half-Life 2 engine are easy to beat with almost all current notebooks and laptops. After all, the HL2 specs were written when the resource-hog Windows Vista was still Microsoft's pinnacle OS. But now there's a mature Windows 7 and Direct X far beyond the version 9 that TF2 makes use of. Hardware-wise any Intel i3-i7 processors have more than enough horsepower. AMD processors we haven't tested but anything made within the last year or two is probably more than adequate. Touchpads are unusable in our experience, as our Dell test laptop couldn't even take commands simultaneously from the keyboard and pad. We recommend a mini wireless laptop mouse (Logitech and Microsoft make adequate ones). Standard graphics on our Latitude were more than adequate as well, same with HP middle-of-the-road laptops.
PC World has a new article on desktop replacement laptops
here. Good read and recommendations. Cnet is another favorite of ours, and they have their own guide
here.