Okay, you want to go native...right? Does that mean native to Illinois or native to USA? Regardless, I am an advocate of pushing native Illinois species. However, there is a little problem advocating native Illinois conifers, since we only have eight of them. Not to mention three of them do not fair so well on most soils.
Native Illinois conifers include jack pine, shortleaf pine, white pine, red pine, northern white-cedar, eastern redcedar, baldcypress, and tamarack. Okay, you said "evergreen", which of course eliminates baldcypress and eastern larch because those two species are deciduous.
Now we are left with jack, shortleaf, white, and red pine; and our two "cedar" species. Unless you have sandy soils, jack, shortleaf, and red pine are probably not going to fair very well.
Finally, we are left with white pine, northern white-cedar, and eastern redcedar. If you want fast growing and native, then go the white pine route. Within 3-4 years of initial establishment the white pine will usually put on 2-3 feet of height growth, annually. Add some diversity and avoid a monoculture by interplanting some northern white-cedar (many different cultivars out there).
Now, if you do not want to go the Illinois native route, you may want to think about white fir, Norway spruce, or even Thuja ‘Green Giant’ (standishii x plicata).
Unfortunately, I cannot recommend one nursery over another. Therefore, you may want to contact your local Department of Natural Resources forester http://dnr.state.il.us/conservation/forestry/DISTFRSTMAP.pdf or the Illinois Nurserymen’s Association http://www.ina-online.org/ for a list of local nurseries to service your retail needs.
Hope this information helped!