Hi Tom,

How many miles did you do since the repair/flush?
If not much, continue driving for a wile, watch the temp and coolant level

There is no mistery here:
1-Evaporation (hole, bad cap, small leak, don't underestimate this one!)
2-Lost of coolant (external, not your case)
3-internal consumption (Big = white smoke)
4-collant blend with oil (how is the oil level-smell-color)
5-very bad bleeding (i doubt this one)

Like another listee did mention, have a coolant pressure test done.
http://www.benplace.com/pressure_test.htm
http://www.benplace.com/cooling_system_flow.htm
http://www.benplace.com/bleeding.htm

Let us know
Cheers, Ben
http://www.benplace.com/ (am working on it...)
73 & 84 Westy