I recently bought a Lenovo ThinkPad W520 for tethered shooting and editing when I cannot use my desktop for some reason. This has been a good machine so far (bought in late November). Purchase tip: much less expensive on TigerDirect than through Lenovo. TigerDirect had the configuration I wanted for around $1300. The motherboard I have can handle up to 16Gig RAM. This requires buying a four-core i7, however. I stopped at the installed 8Gig. Two slots remain for me to use.
This unit comes with a standard Photoshop-smart nVIDIA discrete graphics miniboard that speeds image processing (CUDA cores). Mine is the "1000" board and there is a "2000" with more cores. There's an active forum for questions and Lenovo is OK for support. I have had other ThinkPads. I don't know when a W530 will be released, but if you need one right now I say go for it.
Mine has a higher-gamut "FD" screen that's 1920x1080 and there is a visibly better gamut. Very bright, so can be used for editing in more environments than my last ThinkPad (an X61t tablet)
I made a worthwhile DIY upgrade by installing an mSATA 80Gig solid-state mini drive card in the internal PCI slot, which was empty in my model. (This is the slot used by a WLAN card for cell service.) I transferred the OS into this card and left the spinning hard drive in place as a data drive. (I actually swapped the stock drive for a Hitachi 750 HD during my DIY effort. Super easy.) Having the OS and Photoshop, Lightroom, etc. on the SSD is very fast. I do install some programs on the data drive to keep the mSATA from filling up, but there is some headroom left on this little SSD. This is a solution limited to a very few laptops, because the PCI slot has to be able to handle the drive. I don't know why there are few machines that have this architecture but I know it's the case.
Not a lightweight machine, and the 15.6" screen means it's bigger than that wonderful X61t. But it IS fast and the screen is wonderful. I just made my custom tripod-laptop-support platform out of nice birch plywood, which I enjoyed.
Here's the forum for this line of ThinkPads. Of course, those who have no problems never post, so keep that in mind. But if you are like me I like to look in such resources before a buying decision.
Hope this helps.