Now, I don't know this from experience, but there are quite a few out here. I currently work line at DKB, which is 60 miles West of Chicago. Still trying to figure out how to pay for my ratings and such.
Anywho,
I have met a TON of pilots for Priester and they have had nothing but good things to say.
There is also Dupage Aerospace (
www.dupageaerospace.com) which flies a lot of heavy iron. G-IV, G200, Challenger 601, Hawker, etc... I know the contract pilot they use to get people their SIC in the Challenger. I'm not sure what kinda time you have, but I'll ask him for more info next time I see him (Generally a few times a week) if you'd like?
DBaviation also keeps a pretty good-sized fleet up here but I'm not too sure on the details.
http://www.dbaviation.com/
Those guys have all-kinds of a/c.
N-Jet has an office and operates charter out here as well. I've talked to a few of their pilots and the feedback is mixed.
http://www.nifc.com/
Plane Masters has a pretty good fleet of everything from Freight Caravan's to Small-Midsize Jets (ie. Citation VII)
http://www.planemasters.com/
IFR Charter out of DPA
http://www.ifrcharter.com/
Again, your average 135 fleet.
These are all 135's, but as is the case pretty much everywhere, most of the solid 91 gigs out here will not even consider posting their vacancies on the internet.
I'll ask a few more corporate guys I know and reply if I find anything.