Can you pm your email to me? I'll send you the ad, but I'm sure any good dealer will match it. Unfortunately, if there are only 3 within 30 miles, chances are that those might be it for the 2016 MY since ordering was closed a few weeks ago and 2017 hasn't opened up yet. Even if they don't have exactly what you want, it's still worth a test drive IMO. It might be possible to do a dealer swap at the port, but I'm guessing there'll still be a little wait for delivery. At $35k, it sounds like a Limited with Nav package.
The TLX is an awesome car. Handles really well, quiet as hell, tons of room, and definitely has some pep for the engine. Like I was REALLY surprised at how quiet it was even compared to the IS. I was also seriously considering a TL before I ordered the WRX, but like your IS350, none popped up with the Advance package for over a month, so I just went with a WRX. Pretty sure it would've saved me a few grand in purchase price, taxes, and insurance too, but I don't regret it one bit!
edit: Looks like there are 7 within 50 miles of where I live and Ira in Danvers has a silver one. Quirk in Braintree also has a black one. Both don't have the nav package.