If you apply a layer of teflon tape around the threads on the bleeder valve stem, using the Mity Vac will pull less air thru the threads and make it a more efficient ordeal.
As for a make it yourself power bleeder, see:
http://www.bmw-m.net/TechProc/bleeder.htm

__________________
'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!