Hi,
I became interested in the Great Northern War just a few years ago and, as I didn't know much about the era, decided to use an historical Order of Battle as a basis for both the Swedes and Russians. After scouring the web, I found a site which gave Orbats for an important but mid-size battle (Holowczyn) :
http://wfgamers.org.uk/resources/C18/holowczyn.htm
Although I raised the armies in 6mm, you could adopt the same principle.
I have found the two Osprey books on Peter the Great's Army and their Poltava Campaign guide to be invaluable. [Many thanks to Angus Konstam for these !]
With respect to the Swedish Army, the best book I have found is 'The Great Northern War, Vol 1' by Hoglund & Sallnas (very good but expensive).
I hope this helps.
Phil