Been looking for one for a while now, no such luck. Any heads up were to look are highly appreciated.
The sniffer is very rare,it was made from a Bacharach Sniffer Model 301 I believe,Kingpin has one and is working on releasing measurements so we can make our own Sniffers.
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There y’go! Make one yourself, it’ll be a lot cheaper. 
That’s correct. As I type the side elevation is almost complete, but I have to create the front, back, opposite side and top elevations as well.
Just bought a working Sniffer 301 off of eBay for $99. Unfortunately, it looks like it might only be the actual Sniffer with carry strap, but I didn’t see the pump and rod that you see in the movie. Where in the heck am I going to find those items?
Make them! Some surgical tubing and a blood pressure bulb (available at some health supply stores) and a hollow aluminum rod 3/8" diameter, cross drill some small sensor holes in the tip and a hose barb on the other end, attach some more tubing (should be able to get that stuff at the home Depot)
Here’s my scratch built one
The ‘pump’ can most commonly be found as part of a Sphygmometer. I picked one up real cheap on eBay, cut the rubber connecting tube where it was attached to the cuff and fed the cut end onto a screw which is fitted into one of the plug holes.
The ‘rod’ is an actual product made by Bacharach, probably for the Sniffer. However, it’s a lot shorter than the one seen in the film, so like another Sniffer owner, I got a length of appropriately sized tube, cut it to length and stuck it onto the existing wand. I purchased mine again from eBay, but this item was much rarer.
As for where they can be gotten from (RE: Original poster), eBay. Keep a watch, because that’s pretty much where every one owned by members of the community have come from.
The plans will hopefully be finished some time in 2010.