If i'm not mistaken, GPUs meant for computer modelling (I assume you mean graphics work?) Are typically ill-suited for gaming. Even though they are quite powerful, they don't have the best driver support for a game compared to a typical gaming card. I recently got a 2 gig Geforce 660 SC, and it rocks Skyrim to the ground, including maximum resolution texture mods and ENB mods. My processor is fair being a 2.5 GHZ quadcore AMD Phenom, OC'd to 2.9. Skyrim runs between 40-60 fps at all times.
I think the main question you need to ask is "I if I build a computer to run Skyrim at max settings, will it ALSO support my modelling needs?"
Also, some general advice, Skyrim uses more GPU than anything else. Below is a breakdown of how things work in Skyrim hardware wise:
1. CPU: Skyrim mainly uses CPU for things like radiant story, animation, etc
2. GPU Ram: This ultimately determines how well you can run texture replacing mods before your game crashes. As stated above, I have a 2 gig card, and do not run into any issues running the highest resolution texture mods available.
3. GPU speed: This will ultimately determine your framerate more than anything else
4. RAM: RAM is where Skyrim loads the cell data that you are located in, and stores cell data as you fast travel around. If using Win 8 64 bit, you should have at least 8 gigs of ram. Otherwise, after playing for a while and filling up your RAM buffer, Skyrim will begin to become unstable. All the more-so when you use mods.
Any one of these things could bottle-neck the other however, so make sure not to neglect any single component. You can build a system to crush a heavily modded Skyrim for well under your price point.
Thanks chief, very informative. As I said, I'm mainly using the work thing as an excuse, the stuff I'm doing at home will be anolysis of the data I generate in the lab, it's just easier to slip a big purchase like this past the girlfriend if I can say "Oh no, no, it's for -work-"

I won't be using Win8, I paid good money for a Win7 license and Win8 is essentially Win7 with a daft tablet-style overlay option, so I'll pass, heh. So, given what you suggested, I had a quick look at ebuyer and came up with;
i5 3750k(3.4 stock, supposedly deals very well with a 4-4.2 overclock)
Asus P8Z77-V Socket 1155(I looked at the more expensive Pro and Deluxe versions and, frankly, couldn't see why they were worth an extra £40+ over the normal one, since I won't be running/overclocking the top-end i7s)
Corsair H100
8Gb of Corsair Vengeance 1600Mhz
Gigabyte GTX 670 2Gb "Windforce"(I'm a bit suspect on this one, I suspect the cooler is more for show than anything else)
120Gb OCZ Agility SSD(for the OS)
240Gb OCZ Agility SSD(for game installs)
Comes in at about £950, and if I'm right about the graphics card I could probably get one that's a wee bit cheaper. The 1Tb HDD I have in my current machine will transfer over as it's quite new, and the new motherboard gives me upgrade potential as it supports up to 32Gb of RAM and has x8/x8 SLI support(again correct me if I'm wrong, but from the articles I could find the x16/x16 setups were only gaining about 2-6 FPS over x8/x8, doesn't seem worth the extra for a fancier motherboard just for that). That just leaves the case plus a few bits and bobs - am I on the right track with that lot? EDIT: Oh, and the PSU.