Portable gaming device (PC preferably)?

[al Roumi]

Hi, I have a bit of a connundrum. I'm likely to start traveling a fair bit for my job and I'd quite like something I can do some mobile gaming on. I can't really use my work laptop for this, as I shouldn't and I don't have access rights sufficient to install stuff on it (if I was minded to be naughty). That said, I did try and the only thing i did get to work on it was Dwarf Fortress, which while fun is not enough.

Ideally I guess a laptop PC would do me. However, I do most of my gaming on a desktop and I'm not desperate to sink funds into an expensive but ultimately limited platform that won't have a decent/upgradeable graphics card. I could go for a second hand laptop I guess however I'd be interested in what other options the esteemed Orgahs might be able to recomend...

My main requirements would be:
1. Portable- Light & easy to handle/carry in 1 bag with a(nother) laptop
2. Battery life sufficient for several hours operation (portion of a long haul flights)
3. Internet browsing capability
4. Able to run decent strategy/RPG games -ideally PC type games e.g. from paradox (CPU rather than GPU heavy)

Number 4 is why I'm not interested in a handheld console. I feel a bit old for platformers and linear action games (!) -but happy to be corrected if my perception of the games available is out of date.

A tablet (ipad/android) seems to be a strong contender (bar the price), but I'm not really aware of what kinds of games are available for them -beyond angry birds. I don't have a smartphone so I'm oddly dislocated from what's available on these platforms.

And I guess a laptop would do all the above but would be the least portable, while perhaps also being too much like a PC. In a way, I'd quite like to get some use out of the device when at home and have access to my desktop too -so some measure of different/extra functionality to a PC would also be good.

Lastly, my reluctance to spend too much is becasue my desktop itself is due an upggrade and I don't want to splurge cash for that on something that will ultimately not provide a comparable experience -hence the attraction of something different to a PC.

Thoughts? Any ideas on how much stuff might cost?

Thanks