Mix and Match Troops/Nations

[Rhyfelwyr]

Scotland with Elephant Artillery...

[microbus]

portugal/spain with longbow men

[zstajerski]

Russia and add scottish noble pikeman

[IrishArmenian]

I'd either go the route of ztajerski, or:
Russia with Camel Gunners
Scotland with Cossack Musketeers
Scotland with Camel Gunners
Byzantium with Cossack Musketeers
Byzantium with Camel Gunners
Sicily with Camel Gunners

[Eng]

Any Faction Except the timudris and give them the elephants
Or sherwood archers to Hungary they will go well with battlefield assasains

[llewellyn]

scotland and add cossack musketeers, unstobable pike army then

[FactionHeir]

Do you actually need to add any unit to the slave faction? :p They have every single unit in game.

As for standard playable factions though, I'd go for England with Swiss Guards or England with Elephant Artillery.

Imagine staked circle filled with retinue longbows and having a few elephant arties to take care of enemy siege equip.

[Odin]

Russia and add scottish noble pikeman

I second this one !

[Quillan]

Either Byzantines with Cossack Musketeers or Spanish with Vardariotai.