The New T-Mobile myTouch still does not have an official name yet but if you believe the rumors today it is going to be called the myTouch 4G.
myTouch 4G could be a little confusing as T-Mobile does not actually have a 4G network but does offer HSPA+, which delivers theoretical peak download speeds of up to 21MBps and peak upload speeds of around 5.7MBps. This can be faster than WiMax, which is classed as a true 4G service.
Looking at the T-Mobile website they do make regular references to the term 4G, but do not state that it is 4G just that it can achieve 4G speeds. For example, here’s some phraseology from the T-Mobile website: “Share the love at 4G speeds, on T-Mobile’s new network” and “T-Mobile’s new network lets compatible phones connect at 4G speeds.”
Taking this into account it is highly likely that T-Mobile could name the New myTouch the myTouch 4G, if you can’t call your network 4G why not call a phone 4G instead.