It seems practically certain that this is the case, as T-Mobile has patented the name at USPTO (and specified it's a tablet) and has reserved the T-MobileSnapPad.com, .net, .org, .info and .biz domains.
Sadly, the important details about the device itself and its release date are missing.
Speculations claim it may be the name of Magenta's HTC Flyer or its version of the Sony Tablet S2, but there is every chance that this is brand new, unannounced tablet. Truth be told, there is no way to figure it out, so for now we will wait patiently for another leak concerned with this T-Mobile SnapPad tablet.
source: DotWeekly, USPTO via pocketnow