I don't know of anyone but Scoggins Dickey that can get you the oil pump. Its a pump from the new 2005 5.3L LH6 displacement on demand trailblazers. GM had been hoarding them up till the last couple of weeks. It has a 20% increase in volume, which should help those oil starved bearings.
Part number is 12571885 and cost me $72.72.