Computer in a Power Supply

Recently bought 3 ten year old computers with Pentium 4's ($17 total) from a regional thrift store.One of them had a dead power supply that I opened up and parted out (yay cleaning electrolytic stuff off heat sinks is fuuuunnnn).

I now have an empty power supply with scavenged molex fan, switch, and cable grommet. I could fit a micro-itx board in there but not a full heigth itx GPU and it's a bit big to be used with a PI. I have functional level metal working skills as well as two old cases I can take a hack saw to for parts/materials. I need ideas for what kind of computer I could put in this thing to use it as a NAS, router, or HTPC.

I could fit a micro-itx board in there but not a full heigth itx GPU

APU?

I was about to say the same thing. A10-6800K

I'll certainly look into that, I only have about 6 CM of space to play with here can I get a heat sink that short for an AMD processor?

 

also It should be noted that this is not a standard power supply, it's a strange one and I think the computer with the dead psu might have been a workstation or something at one point.

The new A8-7600 is pretty awesome. I think that is what Gigabyte is using in their mini gaming Brix. Reviews have stated that one can play many games at 1080p with it (former A8's were mostly 720p gaming machines). The chip can run at 65W as wll as a reduced 45W. It is kind of amazing. It could make a great HTPC that one could also use to game on TV (using racing games like Sonic All Stars or classic fun games).

The only downside is that you need a new-fangled FM2+ board, but it sound like you need a micro ITX board anyway.

Although, I cannot find it for sale anywhere. I only see the A10-7700k or A10-7850k (both are kind of pricy for AMD). 

as ever, can I get a heat sink for it under 6 inches tall?

You could use the stock cooler and some good thermal paste if you are not planing to overclock.

no way in hell am I going to over clock this thing. It's in a two inch wider than normal power supply with a single 80mm fan in it. I have plenty of AS5 on hand, I assume that will do?

also also, any good mini-itx power supplies that I can use externally? preferably modular?

http://www.asus.com/Graphics_Cards/GTX760DCMOC2GD5/

The GTX 760 Mini from ASUS is 4.7"... Which fits your needs. 

You're welcome. :D

Pico-PSU + laptop power brick, maybe?