Will a Raid 10 on 2 750GB SSD's and a 2TB HDD work or will I need 2 HDD's?
RAID 10 is like RAID 5 and requires 4 disks of equal size. As it is a RAID 0 that mirrors via the use of RAID 1
You would need to setup two RAID 0's and then manually tell the other to backup to the other.
First let me start off by saying do not do this, its a bad idea and would only slow your system down. Get at least 4 matching drives before attempting a raid 10.
Now that that is out of the way, raid 10 is 0 + 1, and with 3 drives your system is not going to do it with the raid controller set to raid 10. Luckily raid ten is actually a nested raid (or a raid inside a raid). While not a traditional raid 10, you could create a raid 0 between your two SSD hard drives, and then set up a raid 1 between the new Raid 0 VD and your 2TB HDD.
This would most likely have to be done with the raid 0 on hardware, and the raid 1 done through software, unless you have a really good raid controller that allows custom nested raids.
I'm going to reiterate here this is completely pointless endeavor as it would completely negate the speed advantages of SSDs. But I mean if you want to do it for what ever reason, this is how you do it.