Hopefully the 2.5 Liter turbo is adopted into the new Mazda3 at some point... if it is, then I think we'll be seeing the flood gates of tuners coming in.
Tuning companies usually ask themselves before they spend time and money, "is there a market for the product?" With the 2.5T in 2 SUV's and their "family sedan", tuning companies would easily hesitate to invest in a tune for 2.5T... however, the Mazda3 is key here... even though Mazda is trying to get away from the "boy racer" image it once had, that won't stop the fans of the mazda3 from trying.
Another thing is, try finding a decent tuning company, and how about all of us who are interested keep emailing/contacting them about releasing a tune for the Mazda 2.5 Turbo, at least get their attention to know that there's some willing customers out there. I've seen tides turn because customers expressed an overwhelming interest in something that the companies did not consider.
And yes I agree, the 2.5T could use a nice tune, a well done tune that enhances the performance across the board on the power band(especially on the top end of the range to make it more linear) while maintaining MPG's, increasing refinement, etc...while not compromising reliability, it can be done, look at APR's work from the past. The CX-9 as well as any current Mazda vehicle using the 2.5 Turbo could greatly benefit from more power, the CX-9's 0-60 time is average at best, while the rest of the vehicle feels rather premium, it could use extra power to match the package, knock it down a full second (0-60mph in the low 6's) and we'll get the car we all wanted but didn't have.