Make your own:
Green Tea >> Great antioxidant, fat burner, helps metabolize estrogen, increases daily Energy Expenditure...
Caffeine >> Break down fatty acids. Works well with cardio, just make sure it's not high intensity, since your body can break down fat only as fast. High intensity should be done only on days when you do not lift weights, and it's best done as HIT training. Take 200-400 mg.
ALCAR >> help transport fatty acids. It also increases mitochondrial activity and can cause more oxidavite stress, therefore it would be beneficial to add some ALA to it as well. 1-3 grams works best
Tyrosine >> Precursor to epinephrine (you want this substance) 500mg - 1.5 g
Yohimbe >> Blocks alpha receptors >> will help burn belly fat >> 5mg -15 mg per serving is effective, but be careful with dosage since your blood pressure can really jump.
Forskolin >> works through the CAMP pathway and also helps Testosterone
Advantra Z (Synephrine) >> this has some research behind it as well. 20 mg per serving
If you make a good mix of the above, you will make a better fat burner than most offered out there right now.
Here is some research:
http://www.nutratechinc.com/advz/UploadedFiles/JimEnglishArticleVitRes.pdf
http://wingermany.com/Pages/English/healthnews/fruit.pdf
http://www.medscape.com/viewarticle/512890?src=ddd
http://www.markethealthstores.com/images/Hydroxycut/DullooGreenTea.pdf