the armies would be napoleon and other armies of the time, wich means about every color 
i have a lot of the soldiers geobra realeased but they just dont do it for me, as for equipment, they would all have [infantry would] knife, bayonet, rifle, canteen, and small pack, like the one in 4628,
Seawarrior
The term you should use is Napoleonic - this covers all armies around the world that fought or existed at the time of the Napoleonic Wars. That's a lot more specific than 1700s - 1930s. I guess you're thinking 1793-1815, which covers from the French Revolution to the end of the Napoleonic Wars.
If you want a band of 20 men, won't that take 20 figures, or am I missing something? If you want the body & arms off one figure and legs from another, then that'd be 40 men.
20 flintlock muskets & bayonets, plus 20 pouches and/or waterbottles & straps. 20 Hats. These are all best obtained by ordering direct from Playmobil. If you have out-of-stock problems in the US, we usually have the things in the UK which a UK member of the board would be happy to order for you, but allow for exchange rate differences.
If you're thinking multiple lots of 20 men in different uniforms, obviously that's another scale of cost. I'm thinking the upcoming 4690 Pirate Special might make a good basis for a Napoleonic figure, given a different head & hat. 20 of those would cost
me £40 GBP, or about $60 US, then I'd need to add the cost of the musket & bayonet, pack and a hat. Call that another £1 per figure (those little sidepacks are oddly expensive).
I was going to suggest tyat the people at Garden Wargames would be better equipped to help you with your questions, as thet have already created many different customised uniforms from Playmobil parts, but I see you have already asked the same question there.
