I believe the answer to your specific question is no; the only boots I know of with tech fittings are hard boots made of plastic or carbon fiber. However, I think you may be underestimating those boots.
AT boots are hard plastic but can still offer a soft feel. Transitioning to skinning uphill consists of not just unlocking the heels but also switching the boots to a walking mode.
In walking mode, many feature a wide range of cuff rotation. For example, the Dynafit TLT6 boot offers a cuff rotation of 60°, and the recently released Atomic Backland offers an impressive 74° rotation. This means you can actually walk reasonably comfortably in them as opposed to being forced to clunk around as you've likely seen people do in alpine ski boots.
Depending on the boot you may have additional options. The older TLT5 model offered about 5mm of flex at the toe, and many boots feature removable plastic tongues that you can take out if you want even more softness. AT soles are usually rockered (curved, like hiking boots) to improve walking.
Weights for the lighter weight models range from around 0.8kg to 1.3kg per boot (or as little as 0.56kg if you have the cash).
Finally, you may also wish to consider telemark (aka 3-pin) boots and bindings. You won't be able to lock the heel but the telemark turn offers an alternate way to tackle steeper downhills. (And with good technique you can still pull off parallel turns.)