FWIW I made one a few months... still missing the power but the mac-ness of my 2006 mini is worth it (WHY...WHY do they use really slow integrated graphics though?!?)
Basic stats...
- gigabyte H61M-S2PV mobo
- i5 (3500+ or something, I forget the number.)
- 8gb RAM
- Numerous graphics cards until one worked (Radeon 550ti with 2gb VRAM)
- Mountain Lion
2tb HD
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Really powerful and only set me back about $400... I got it working 100% then went through some life changing events so sold everything in a fire sale.
Now I use a 2006 mini and a G4 mini. Looking to upgrade but currently saving for a wedding so maybe later?