So I think I've figured out my rough design. I'll elaborate more on my build thread but it basically goes according to the picture I lovingly drew. I'm thinking of also using those tripath amps but need to find out how gainphile powered them. All-in-all it could turn out to be a very cheap build (objectively)
I will be using switched Power supply unit from sure electronics.
"24V DC 14.6A 350W Regulated Switching Power Supply"
It just arrived today so I will have the whole amps assembled this weekend.
The whole thing is experimental to me. Both the Class D amps and the PSU especially the fan (it's supposedly temperature-controlled, not on all the time). It's because I don't have the energy to build and solder gainclones which I know is sonically transparent (although I already have all the chips and audiosector boards).
The amps are two of "4*100W TK2050 TP2050 Tripath D-class Amplifier Board" from Sure Electronics (eBay).
Total cost for the 2 amp boards (8 channels total) + 1 PSU is $160. I'll add $80 for casing and connectors.
The driven speakers are 4-way dipoles. Today they still lack the last bottom octave as a 3-way. But ok 90% of the time except synthesized music stuff. The subwoofers would be dipole W-frame subs for 20-40z as used in SL's Phoenix.
Maybe at that time I'll add the 2nd PSU.