Spec me a mini ITX build

I'm thinking about getting rid of my current massive air 540 watercooled rig in favour of something a bit more sleek.

I currently have crossfire 290s but as games are supporting crossfire less and less I'm thinking about just ditching the two and going for the one card that will get me similar performance to the one 290.

Current spec:
3770k
2x 290
16gb Ram

Can I cram an upgrade into the small space and price of ~£800?

Also any suggestions on cases would be great, I really like the lian li PC05 but it's ridiculously expensive.

silverstone sg05. Beautiful small case

I have a 970, i7, 16gb, 120 aio watercooling (corsair h50 i think) and a 450w silverstone modular sfx puower supply

I have a cooler master Elite 130. Which I really like, small footprint but fits full sized gear.

If you really like the lian li PC05 but want to save some pennies, the Fractal Node is very pretty and quite a bit cheaper. Would need to get an sfs power supply and not all graphics cards will fit though.

Would recommend the SG05 also.

See the case gallery in this section of the board...mine is the most recent post.