That's rough mate! I would never buy anything from China specifically for fear of scenarios like this! 90% of the time it's probably ok, but if something goes wrong you're in trouble..
So, down to business. First, im not sure that flashing a stock rom on a root would have the effect you're talking about as the boot sequence should at the very least start up, if not just repeat over and over because it's impossible to tamper with the boot kernal on milestones. So really it should be fully intact, which would mean the phone is always recoverable. Question number one is, are you talking about a Milestone or Droid? Because the Droid's kernal could be f'd, in which case you're in trouble, but a milestone's one will (should) be ok.
Also, with a milestone you press power on + camera button to go into recovery, not d-pad.
If you do have a milestone and not a droid it might be worth taking out the sd card and use a card reader with your PC to put an Update.zip on the root of the card, then see if you can get to it via power on+camera, then volume up+camera. I don't know whether i should be telling you to use an official update.zip, the update.zip that gives root, or a Rom update.zip i'm afraid though. If i were in your shoes i think i'd probably try the
Pulsar Rom update.zip (+ associated files)
I assume you've been here to get the stock rom in case your current one was corrupted?
Tbh I don't really know, but i find it very strange that the phone won't even start a boot sequence. Good luck and let us know how you get on.