All I can tell you about is one that I've seen with yohimbine from Rauwolscine extract which is mostly alpha-2 antagonism combined with Cirsium Oligophyllum extract which is a beta-2 agonist in supplements before. The Cirsium Oligophyllum appears to have mild effect at this receptor.
Keep in mind that alpha antagonism and beta agonism is almost like the opposite of the blood pressure meds clonidine or guanfaine which are alpha-2 agonists and beta blockers for blood pressure granted they block action at beta-1 which are more cardio-selective.
I wouldn't, but if you're hell bent on doing it tread with caution. If I was going to do that, I would learn how to take my pulse and blood pressure and learn how to interpret those readings. Or better yet, frequently see a sympathetic doctor who can check up for all those things.
Also, like you said you were going to do, I would try each one out on its own before making any sort of combo.
I hope that your diet is already squeaky clean and that your training routine is appropriate for fat loss already. If not, I would work on that before playing with my body chemistry.