What kind of reptile should I get?

I want a reptile thats big enough to hold. I've asked my mom for a bearded dragon, but she says no, for some strange reason. I'm not interested in Leopard gecko or anything tiny like that, I want something big enough to hold, but not too big where he takes up half of my room, ya know..like, maybe something that can fit in a 20 gallon tank or a 30. I prefer 20 gallon. I've also talked to my mom about iguana's and she said no. (She said no to alot of my suggestions) I've been doing alot of research..but I'm inept at finding things. (By the way: I also asked about snakes and it was a no. go figure, right.) Help please.