@quest for silence: As far as I can tell there are no sandy-bridge based mini-itx mobos other than H67, h61, or Z68 chipsets. The OP needs mini-itx board for the Q11.
@ the OP: Check out this thread: http://hardforum.com/showthread.php?t=1523097&highlight=fanless
It has a ton of info on the Q11. Some users in this thread, such as on page 32, have used a Silverstone Strider ST50F-P modular 500W PSU. It is small(ish) at 140mm deep, still modular, and as pictures in the thread show (http://hardforum.com/showthread.php?t=1523097&highlight=fanless&page=32
) it has enough room between the intake fan and the butt of the PSU for airflow, plus the ends of the modular cables. (Click on the guys' photostream and scroll to the beginning to confirm that he did indeed use a Strider 500 plus.)
One note of caution--the PSU is rated at 40 C and not 50 C, and the Q11's small size has led some users to high internal temperatures. Not sure if this will be a problem but caveat emptor. (Myself, I went with the Strider and plan on crossing my fingers with good cable management.) Another option is the Silverstone st45, which is a 450w SFX powersupply (comes with an ATX bracket) which many users have also used in this case. Although it is not modular it is also much smaller and perhaps ultimately a better fit.
I just bought a Q11 build (awaiting its shipment) and I went with the MSI 6850 Cyclone and the ST50-P. According to several reviews as well as one of the threads on this forum, the Cyclone is one of the quieter mid-range video cards, and it is also one of the smallest. It was confirmed in that [H] thread that this card fits in the Q11.
If you are getting the 2500K, know that your OC'ing abilities are limited (I think you cannot OC at all) on an H67 board. You will need a Z68. As of now there are only two min-ITX z68 boards by ASRock and Zotac, and I hear nothing but bad things about the Zotac board. If you do not plan on overclocking, I would recommend either the 2500 (non-K) or the 2400. Personally, although you are getting a discrete video card I would still go with a Sandy-bridge CPU at this time, as they out-perform previous iterations and also outperform AMD's current offerings according to benchmarks. For me the integrated graphics is surplusage; the CPUs are still pretty competitively priced even if the integrated graphics were not included.
Hope this helps.