I dug arround the web for additional info regarding the FC10 case.
On a news article on anandtech.com, "Ganesh T S" one of the anandtech staff people and the author of this news comments the following:
(you can see it here: Streacom Updates Passive HTPC Chassis Lineup with FC9 and FC10
Streacom indicated that they could have shaved $100 off the price if they had used an ordinary aluminium chassis instead of extruded aluminium.
I asked Streacom about this, and they indicated that in their tests, up to 120W TDP processors had no problems getting cooled with just latching on to one side of the chassis.
Streacom just mailed in with further clarifications.
All the PSUs on their site listed as compatible are non-power brick models. They apparently mount on the chassis.
The "underutilized" heat dissipation fins are apparently meant for GPU cooling.
Also if you look at this FC10 Computex picture you'll see a "standard" ATX power connector and also that silver thing inside is a PSU.FC10 Computex photo
You can see the PSU better in this picture: FC10 Computex PSU
The translated text from german to english is: "New internal power supply in FC10 - of course completely passively cooled, high-quality aluminum body."
Apparently they changed their mind because the currently FC10 advertised on their website has a power brick connector not a ATX one: FC10 currently on Streacom website
Also, on their website at the FC10 specifications tab there is this particular mention:
"Power Supply: Nano150, Nano150XT, Nano180XT or StreaFlex 250 (not Included)"
But only the Nano150 PSU is listed as accessories on their site ... as of right now one could not find any informations regarding the other three PSUs.
In particular the "StreaFlex 250" sounds very interesting because a good 250W PSU can power a decent mid-gaming system!
Maybe they will keep the part with the right heatsink used as a GPU cooling device. That would be nice indeed