Fusing Molds

I want to create a nice little jewel of mold the size of a tape (think breast cancer ribbon pins.) Could Sculpey, cooking, handle up to 1700 degrees F Time?

Absolutely not - it is - PVC pipe as water.
Your best bet is to buy pottery clay gray or white and cut the mold or press it in the original (as you've probably been to do with Sculpey, then dry and fire in your oven - all what he has to do is get a little warmer than your merge. It helps (may be necessary, but I still do) use a separator or glass kiln wash on the mold clay. If precision is required, the allowance should be made for both clay and shrinkage of glass. My use is recorded here Clay http://users.ticnet.com/mikefirth/warmgl. .. is not shown on the vertical piece mold in the first image on the page that was white clay, resting on a cookie sheet-shaped biscuits square.

Probably not consider it clean process that happens in the temperature range in a kitchen oven. In fact, I saw Sculpey start burning in a furnace. But if you can reach temperatures of 1,700 degrees F. Why not use clay to make ceramic mold? Or get a piece of firebrick that is soft enough to carve out and control what you want?
Link to Sculpey which could have some technical information available.
http://www.sculpey.com/

No, it will burn. It will burn at 350 in the oven, it will be incinerated at 1700.