The answer is something you might not embrace. Mamianka is the only truthful person who has answered this question thus far. Placido Domingo is known for being a starter baritone who developed his instrument to sing tenor material. I love him (one of my favs. Maybe that's why I love him), but I do believe he might indeed be a true baritone or a middle of the road type singer (in between baritone and tenor). BUT Placido Domingo was SMART and has an interchangeable voice. He is very knowledgeable about voice mechanics and his own instrument. He knew what roles to play, and what roles to run from. Most singers, even professional ones, don't know how to do that. The danger of constantly singing out of one's vocal fach is huge. Many singers develop vocal nodules and sometimes it can even cause permanent damage. Be careful.
As a low voice singer with a wide range, I will occasionally take a soprano solo or two in an oratorio piece IF it is comfortable. I've even done Zerlina numbers from Don Giovanni every now and then (in my defense, many companies are hiring Mezzos for that role since it doesn't stay high in the average Mezzo's tessitura) I can vocalize as far as an operatic lyric soprano, but I know my instrument. Sure, I have a pretty high range, but that doesn't change where my transition is in the voice. Range has nothing to do with voice type in my case and MANY others. You can only tell my voice type by listening to the transition and the quality. Especially in my bottom range. My bottom range is much heavier than a dark dramatic soprano's bottom. It still has a dark quality to it, just as Placido's does. So no matter how much I would LOVE to play Liu in Turandot, it's not going to happen. Sure I could sing it. I could definitely sing the notes. But at what risk to my instrument in the long run? Its not about singing high notes. it is about what feels most comfortable in the voice. If you ever take an in depth vocal pedagogy class, you will understand why trying what you want is a big no no physiologically. Anything not natural and forced will eventually backfire by nature through damage.
As a Mezzo, I know how you feel. It seems like the Sopranos and Tenors get all the glorious roles, and it seems like they have more fun. But the longer I work in this field, I realize the low voiced singers are valued more. There is less drama, less competition from back biting jerks who want to sabotage your gift. Not only that, I LOVE playing villains. I love looking at the shock on people's faces when I sing extremely low notes. Men have told me they think it is "sexy" and "milky". I don't mind that at all. I find it to be a compliment. Baritones have the most romantic voices. I have a friend who's baritone voice make women melt. It is too bad that he is gay...but that is another subject.
I was tempted into that trap. I could be a nut and market myself as a soprano. But that would be the biggest mistake of my life. It would cut my career short, and I would lose work. People can see through a person who is truly one vocal fach trying to be another. The one most comfortable in that voice type will get the solo or role. Remember that. Professionals hear right through it. Most voices are not Placido's. Sure it is fun to play around with range and hit high notes. There are plenty of Baritone solos and roles that will cause you to display high notes just as there are Mezzo solos and roles that do the same. It doesn't mean you have to hide your high notes. It just means you need to be accepting of your gift. And no, size doesn't always determine range. Another friend of mine is extremely short, but her range is HUGE. She is however, a contralto. Sometimes, I think it gets more complicated than size and body type.
Accept who you are vocally. I get so tired of watching people get nowhere trying to be something vocally they are not. The quicker you accept you are a true baritone, the better response you will get from the audience, the more musicianship skills you will develop, and the more you will accept yourself for who you are. This is deeper than "I want to be a Tenor". It is self acceptance as a whole. Love who you are. Be who you are. Don't be ashamed and embrace it. Those who embrace their differences from others are the ones who are the most successful. Not the ones trying to be like everyone else. It certainly didn't stop Ben Tyrfel. His name is more famous than most Tenors in his generation.