Toss one of these in the doorway. 7200 CFM, you might want to skip the frame or open a few windows before the roof decides to fly off.
24" High Velocity Floor Fan
One of these would be more reasonable though for the average house, but overkill for anything even a little bit tight or not fairly large. Might still need to open a window. Since it's an axial fan it might be be able to generate that much pressure though. If it were actually a blower(sirocco/squirrel cage type) like a furnace blower, it would.
8" Portable Ventilator
If it were just for vermiculite remediation, couldn't you just load every window with a box fan? I got 5 box fans off a guy on craigslist for $40 in order to do some pretty serious cross ventilation, works like a charm. Decided to point them all outside with the windows shut and I was getting a similar amount of air drawing down through the furnace draft opening that I did when the house was at 50 pascals but I'm certain I wasn't there as axial fans don't perform that well under pressure since the air essentially leaks back through the corners and between the blades due to the nature of their design.