I'll back up what Mad Doc Morris said. Uniformity was something that was only dictated by 'fashion', very much as now, so while everyone was wearing similar clothes, they came in a variety of qualities and colours. The wide range of figures available, while usually generically termed 'Italian Wars' or 'Renaissance' often cover a wide period within even the same ranges. If you imagine the variety of clothing styles between say 1955-1980, and then imagine mixing all those styles together, you'd get some very anachronistic units.

The Lansknecht 'style' itself went through several variations over time and each country had its own style variations initially. As units went from their own country to wherever the campaign was taking pace, they lost their distinctive look as they were forced to replace clothing from the local area, or from the battlefield. Therefore in Italy, for example, Spanish and French troops that had been 'in country' for a while would most likely look relatively identical and comparatively 'Italian' in comparison to fresh troops from their respective nations.
Armour is also a complex subject as there were considerable differences between items produced in different countries. Germany and Italy were the centres of armour production and other nations copied their styles to an extent. The richer you were, the more up to date your armour. The less wealthy would be wearing cheap 'ammunition' (mass-produced) armour along with older styles and anything else that they could loot from the battlefield, this might therefore be a very eclectic mix.
The Assault Group do an excellent and expanding range for this period and I believe
Crusader Miniatures were showing some Lansknechts recently too.