I ended up, kinda to my surprise, with a just refurbished explosimeter - this is a current production item, factory serviced/calibrated 11-24-09 - I set the ebay start price at about 10% of new, figuring that anyone who could use it would jump at it but I wouldn't risk giving it away for 99 cents - here's the link
At least read the instruction manual (link on the auction page) that is pretty interesting - it uses a platinum filament to measure combustibility