I'm a bit confused; a gram is a weight measurement (actually mass), but your post is for a pressure transducer. Which would you like to measure--force or pressure?
The range (0.1g ~ 0.03 oz ~ 0.002 lb) is rather small and on the order of instrumentation-quality, which means expensive. Of course, anything can be done. I once used a force transducer that could measure that range with only mediocre accuracy that cost about $250 that I got from Omega. If you want highly repeatable force measurements on that order, it may cost $1000.
Now, if it's pressure measurements you're looking for, a gram doesn't make sense because it's not in the units of pressure. I'm not sure how to proceed from here on that one;..
Short answer--look at digikey's pressure and force transducers and at Omega (www.omega.com). Watch that with most transducers (especially those of high precision/accuracy) you'll need to buy a signal conditioner which amplifies the signal to 5v at the max output. Those can often cost as much as the transducer itself.
Thanks, I might have gotten a little confused when I posted. I'm just trying to make a digital scale that can measure down to the tenth of a gram range. I've seen a few scales for about $30 that supposly can do this but i thought that seemed a little cheep.