is there any way to calculate exactly how many combos you can make in FOC character customization once the game is officially out?

Where there's a will, there's a way. Pity I do not have the will power for such a complicated question.

I don't think we know exactly how many parts, colors, abilities and weapons there are, so I don't think so.

I believe I can help you I made a thread about it http://www.tfw2005.com/boards/transformers-video-game-discussion/627594-customisation-cominations.html I worked out that if there are 8 parts (judging by screenshots at the time, it seemed correct) for each of the 6 sections of the body then there is going to be 262,114 armour combos for each class NOTE: this does not include any colours, decals, metallic, non metallic, voices or personalities so there will be more combos than what I said as I was focusing on the armour options

A x B x C x D x etc. It's really simple. Count the number of options in each category and multiply. Meggamus did the armor bits. If you want to include color options, count how many primary colors there are and how many secondary and multiply them and his number together.