There are already a couple on Gunbroker.com. It looks like the "M" stands for match. Here the description from one of the sales and and here is a link to another with some photos
http://www.gunbroker.com/auction/ViewItem.asp?Item=99432607Springfield XD(M) 40 Caliber Bitone PistolSpringfield ArmorySpringfield XD(M) 40 Caliber Bitone Pistol Now In Stock!. New Springfield XD(M) 40 Caliber Bitone Pistol With 4.5" Match Barrel & 2-16 Round Magazines. Completely Redesigned Frame & Slide.
This is the most exciting pistol to come out of Springfield Armory since the introduction of the XD Pistol. This pistol is the result of 2 years of work from the minds at Springfield, and the final product is fantastic
The Slide:
This model features a Stainless Steel Melonite Finished Slide which has been completely recontoured & angled, a 4.5" Match barrel, upgraded rear sight (compared to the standard XD), and aggressively angled & cut front & rear slide serrations
The Frame
The full size polymer frame has been completely redesigned and simply feels more ergonomically correct. It features interchangeable back straps, smooth trigger, and Picatinny rail for all tactical lights and lasers. The total weight for the firearm is around 32 Ounces without magazines. (2-16 Round Magazines Are Included
The Rest
The Springfield XD(M) comes with 2-16 round magazines, holster, accessory kit & hard case
Slide, Match Barrel & Polymer Frame Are All Serialized
It is a safe bet that the new Springfield XD(M) will be in the running for Handgun Of The Year. Matte Black versions, and larger qty's of the Bitone XD(M) pistols should be available very soon
Not For Sale In CA, MA, NJ, NY, or DC
Product Features
* Springfield XD(M) Model
* 40 Caliber
* 4.5" Match Barrel
* Recontoured Slide
* Upgraded Rear Sight & Standard Front Sight
* Completely ReDesigned Frame
* 2 - 16 Round Magazines
* Accessory Kit Included (Holster, Mag Pouch )
* Hard Case Included
* Slide, Frame & Barrel Are Serialized