Pride is for everyone. Splintering won't help anything. It's much better to work on increasing visibility at existing Pride celebrations than to try to create our own.
Basically, Pride works by showing off the overwhelming numbers of queer people and allies in our communities. It's so big and so popular and so loud that it forces people to recognize our existence and maybe even overestimate our numbers, because so many straight allies and non-gay sexual minorities show up. You wouldn't get that with trans pride - our numbers are much smaller, we have fewer allies, our cultural history isn't half as much fun (so we wouldn't draw the mainstream revelers), and the biggest problem of all is that a lot of trans people aren't/don't want to be out as trans. It's hard enough to get straight trans people to show up to Pride and be out as "generically queer" - having to be out as specifically trans would be way too much.
So you'd have a very small turnout, almost exclusively consisting of politically-active genderqueer types and maybe some drag queens. Who, by the way, are great. But they don't represent the trans community in general, despite being the most visible face of it. You'd face the double whammy of small numbers and a crowd that consists mostly of visibly "other" people.
