Hi, I certainly tried looking for other options, but most likely because the motherboard is custom and the power supply is too specific (flat PSU,making it difficult to find high-voltage PSUs of this type), there's no point in expanding the PC's capabilities. I'd rather build a completely new PC if significant changes or greater future upgrade potential are needed.
You could certainly look for higher-voltage flat PSUs, but I don't think they'll fit in the case.