Hello,
While that button is available in the HikaShop backend, I didn't see the need in HikaMarket.
Since there is also some possible restrictions/limitations in the number of product that a vendor can create, it adds some complexity in the development.
To add that button, it requires to modify the HikaMarket product controller to implement the "save2new" action (which is available in the HikaMarket category controller).
Then it would be possible to modify the HIkaMarket product view in order to add a new button in the toolbar to perform that action.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.