Below is a list of power supplies you will see for sale followed by the companies that actually manufacture them:
A+GPB- Topower
Akasa- Enhance
Antec- ChannelWell
Aopen- FSP Group
Aspire- Youngyear
Athena Power- Topower
Chiefman- Powmax
Chiefmax- Powmax
Chieftec- Sirtec
Coba- ATNG
Coolermaster- AcBel Polytech
Coolink- ATNG
Coolmax- ATNG
Demon- Powmax
Enermax- Enermax
Enlight- Sirtec
EPower- Topower
Fortron- FSP Group (same company)
HighPower- Sirtec (same company)
Hi-Q- FSP Group
Hi-Val- Topower
Logisys- Youngyear
Lead Power- ChannelWell
Mad Dog- Topower
MGE- Youngyear
OCZ- Topower
PCMCIS- Topower
PC Power & Cooling- PCP&C
Powerman- FSP Group
Powmax- Ultra
Raidmax- Topower (XP Series)
Rosewill- ATNG (AP models), Youngyear (RE models)
Silverstone- Enhance
Sparkle- FSP (same company)
Startech- ATNG
SuperFlower- Topower (same company)
Tagan- Topower
Turbolink- ChannelWell
Thermaltake- Sirtec
TTGI- Topower (older ones), Youngyear (newer ones-?)
Turbolink- ChannelWell
Ultra- Wintech, Youngyear (X-connect ?)
Ultra X-Finity- Wintech
Vantec- Topower
XClio- FSP Group
Zalman- FSP Group
Zippy- ?
Disclaimer- this is by no means a comprehensive list and may not even be totally accurate. Many of them have been verified, but there may be variances within a product line. Also, just because the same manufacturer OEM'ed a product for a vendor doesn't necessarily mean that it is the same as a product from a different vendor since a vendor may take the OEM product and upgrade it with better components or they may give the manufacturer a tighter set of specifications.
A+GPB- Topower
Akasa- Enhance
Antec- ChannelWell
Aopen- FSP Group
Aspire- Youngyear
Athena Power- Topower
Chiefman- Powmax
Chiefmax- Powmax
Chieftec- Sirtec
Coba- ATNG
Coolermaster- AcBel Polytech
Coolink- ATNG
Coolmax- ATNG
Demon- Powmax
Enermax- Enermax
Enlight- Sirtec
EPower- Topower
Fortron- FSP Group (same company)
HighPower- Sirtec (same company)
Hi-Q- FSP Group
Hi-Val- Topower
Logisys- Youngyear
Lead Power- ChannelWell
Mad Dog- Topower
MGE- Youngyear
OCZ- Topower
PCMCIS- Topower
PC Power & Cooling- PCP&C
Powerman- FSP Group
Powmax- Ultra
Raidmax- Topower (XP Series)
Rosewill- ATNG (AP models), Youngyear (RE models)
Silverstone- Enhance
Sparkle- FSP (same company)
Startech- ATNG
SuperFlower- Topower (same company)
Tagan- Topower
Turbolink- ChannelWell
Thermaltake- Sirtec
TTGI- Topower (older ones), Youngyear (newer ones-?)
Turbolink- ChannelWell
Ultra- Wintech, Youngyear (X-connect ?)
Ultra X-Finity- Wintech
Vantec- Topower
XClio- FSP Group
Zalman- FSP Group
Zippy- ?
Disclaimer- this is by no means a comprehensive list and may not even be totally accurate. Many of them have been verified, but there may be variances within a product line. Also, just because the same manufacturer OEM'ed a product for a vendor doesn't necessarily mean that it is the same as a product from a different vendor since a vendor may take the OEM product and upgrade it with better components or they may give the manufacturer a tighter set of specifications.