You are not going to find an ultrabook with an optical drive because to qualify as an ultrabook it needs to be excluded. Additionally, you are not going to find an ultrabook with the Intel HD 4600 graphics core because all ultrabooks must have a ULV (ultra low voltage) CPU in order to qualify as an ultrabook. Therefore, you will have to settle for a CPU with the Intel HD 4400.
You can consider the recently released 12.5" Lenovo ThinkPad X240. It starts at around the weight you are look for; a base weight of 2.84lbs / 1.29kg.
I was playing around with the hard drive / SSD configuration.
Personally, I would simply go with the hard drive. That gives you the option to select a 16GB M.2 SSD cache, when then gives you the option for a 2nd M.2 SSD slot (they call it 3rd though, not sure why). That means you will can install a standard 2.5" SSD drive and have 2 available M.2 slots for future M.2 SSD drive upgrades. When I checked prices of M.2 SSDs back in the fall, they were 2x the price of mSATA SSDs.
If you choose to configure the X240 with a SSD, then it seems you loose the 2 M.2 slots for future expansions.
Therefore, I would just get the X240 with the hard drive and buy a SSD instead. Simply clone the HDD to the SSD and make a recovery disk. The HDD can then be turned into an external drive later.