Certainly does. I have one right in front of me. It has a 44pin laptop HDD connector, a 40 way 0.1" header and a socket for a standard 3.5" hard drive power connector. And a tiny bit of PCB in between.

As for going the other way, then yes I also have a cable that has a 2.5" 44 way connector on one end and two 40 way connnectors on the other. You don't need a power connector since in this case you'll have the power socket on the 3.5" drive.

Shouldn't be too hard to find on computer web store somewhere.