sorry to hear! i must say i once had a brick and gave up only showing a red led1 i believe it was on a my nexusS? i gave up ass i messed up the bootloader aswell.. nothing worked, than i decided to unscrew the motherboard disconnected everything and took it apart as i could only regain some of that cash to buy a replacement if i sold it as parts except for the faulty motherboard. i stored it away a couple of days as i made advertisements for the parts.I use Xposed on another android device for a few adjustments.
I tried every combination, they all lead to the same result. For now im going to leave it uncharged and charge it again tomorrow and try if i can somehow get into fastboot, but seeing that i only get the white screen, i am afraid that it wont really have any effect to wait.
later i decided to put it together again as no one really interested int the parts and sell it as is! miraculously putting it back togather and being of power for a cuople of days resetted the bootloader, or maybe it wasnt completely damaged! i managed to flash back stock rom and it worked ever since, up till the day i sold it anyway to go for an upgrade on the device..
great story just not sure any of this would matter to your problem, but i might see if you got nothing to loose it might be worth disconnecting the motherboard carefully for a couple of days and putting back together and a full charge!