The ABC rooms at West Sub are for "traditional" births (ie less interventions, more like birth is supposed to be) - not the other way around! I think only the midwives can see clients there, though.
Incidentally, even with an autoimmune condition you may be able to see a CNM for most of your care. (I would ask; frequently even if you "risk out" of a midwive's care she will usually co-manage your labor/delivery with her partner OB, which gives you the best of both worlds - one on one care and labor support from your midwife, and extra medical oversight from the OB).
West Suburban Midwives Associates in Oak Park (http://www.westsubmidwives.com/index.html) are really really fabulous. I saw Gayle and Julie for all my prenatal care and would have delivered at West Sub but they can no longer do VBACs for insurance purposes (a situation that will hopefully change soon) so I had to switch my care at 30 weeks and delivered at UIC instead.
Honestly, I wasn't too wild about the non-ABC rooms at West Sub. Then again, I would stay far away from Rush b/c of their very high rate of interventions (in 2007 they had a nearly 50% c-section rate!!!)
Do you need to stick to the Oak Park/Maywood area? Because I had a really great experience delivering at UIC and I thought the care I got was medically excellent, but also that they were very respectful of my birth wishes. Most importantly, I thought their practice was very evidence based; when there was a decision that needed to be made one of the doctors very clearly spelled out what the risks and benefits of each choice were and then left the decision up to me.