The same here with my Q11 build ,everything looks good an clean until the PSU is installed ,then it is a mess and airflow is restricted. I think the ST45SF or a full size PSU+Lian Li psu extender are a must in this case.
btw.nice build there crazjayz
Just finished installing my new AXP-140 into my PC-Q11 ,what an amazing heatsink . I´m running it fanless and my i3-540 @ 3.6 is maxing out at 56º (23º ambient) that is almost 20º cooler than the stock intel hsf. I´m really happy as this should give some more overclocking headroom ,I´m aiming...
You might want to take a look at the Msi Radeon 6850 Cyclone PE ,it fits perfect in the Q11.
I have one installed in mine.
http://img560.imageshack.us/img560/7826/dsc02141tl.jpg
You should be ok with the Q11 . I´ve traveled with a bigger case (Sugo SG-01E) as carry on in the past without a problem. didn´t try with my Q11 though.. for a nice bag I suggest this sugo pack http://www.silverstonetek.com/products/p_contents.php?pno=sugo-pack&area=
very nice build quality