Hi,
I want to say that everything is possible but it will require some customization of custom development.
You can have a checkout system in HikaShop without payment method, the order will be automatically validated.
You can also use a "simple" payment method like "collect on delivery" which just validate the order to a configured order status.
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.