Here are some illustrative images:
Reconstruction of Leczyca,middle Vistula, Poland - hillfort form the end of the 6th century (although, inner wall was probably simplier in this period)
The area today:
Link to a document containing examples of early slavic houses (the document contains english and german overview of the subject)
http://archeologia.fphil.uniba.sk/at...3Salkovsky.pdf
The hillfort Stradów, biggest slavic hillfort in Poland:
Reconstruction of slavic settlemnet with small cirkular hillfort in Gross Raden, eastern Germany:
Reconstruction of slavic shrine in Gross Raden
Gross Raden gate of the fortress (tunel in the earth wall) and view on the village from the walls of hillfort:
This seems to be german page dedicated to slavic fortified settlements:
http://slawenburgen.npage.de/mecklen...mmern-a-m.html
Example of Great Moravian curtis form the late 9th century in Ducove (near the town of Piešťany) western Slovakia:
Area today (partialy reconstructed):
Here you can find pictures of various technologies of wall construction:
http://www.hradiska.sk/2010/05/konst...h-hradisk.html
Wall construction of Great Moravian hillfort Gars Thunau in lower Austria:
Hillfort Tlmače, central Slovakia, an examlpe of hillfort built on the natural hilltop:
Reconstruction and map of Mikulčice (Southern Moravia, Chech Republic), the bigest found Great Moravian settlement, possibly capital of the principality. It is also one of the few south-moravian hillforts founded alredy in the 7th century.