Depends on where you are located. In my area that are many private 4d/3d ultrasound places to do what you are asking for. They are not for medical purposes but strictly fun to have keepsake pictures and possibly find out the sex. As PP said try to google 3d ultrasounds and then your area hopefully there are some around you.
Re: Sex of my baby:)
DD - January 2016
@RepeatPostPolice
Omg, I'm lucky just to be gif-ing. You are amazing.