Alright, I have a few mATX cases and my fiancee would love to be using one of them (she's currently using my Shinobi XL).

Fiancee System Specs (roughly)
Intel i5-2500k Processor @ 4.0 GHz
P68 ASRock Motherboard
2x4 GB DDR3 1600 MHz
120 GB SSD
AMD 6870 1GB GPU
1080p 21.6" Monitor

She uses this rig for graphic manipulation/creation (Photoshop) as well as play games (by herself or me, but new/newer games like Borderlands 2 for example).

The problem is that she has an 1155 ATX Motherboard. The only mATX or mITX motherboards I can find for 1155 are all the H or B series, which means you cannot overclock her processor (which is a 2500k at 4.0 GHz).

I have read some reviews that show 1150 i3s will lower/limit down the possible frame rate that she would be getting compared to an i5 overclocked at 4.0 GHz. Though I could easily find a 1150 mATX or mITX motherboard and toss that into a rig.

With that said I was thinking of either throwing in a i3 into her old system and let it run as a server (it is now but would be nice to have it dedicated for that). I have the Shinobi XL, but I have no idea where I would put it, I could potentially get a rackmount/low profile long case, put it under a coat-rack near my home theatre set-up and go from there. If I were to do that, would the Shinobi XL have a decent enough resale value (probably locally) to help fund that case change.

No 1155 overclockable mATX out there anymore, need alternative solutions.
Shinobi XL to rackmount/low profile long case could I do it for a minimum cost/loss if I sold the Shinobi XL