When I was facing COBRA last year, I called my auto insurance agent and he found me a policy. Mine was through Humana, and it cost about $120 per month for an 80/20, with no Rx coverage, but I forget what my deductable was.
I had to answer a ton of questions over the phone, and they pulled up my pharmacy records and asked why I was taking this that and the other. I did get the coverage, but they excluded any lower back sprain/strain injuries, since I had just finished a pretty pricy run of physical therapy for my back.
I carried the policy for 2 months while I was between jobs.
As for denial, you can't be denied for pre-existing if you've been consistantly insured. If you let insurance lapse for longer than a certain time period, then you can be denied. That's why you get those proof of insurance letters whenever you change insurances. I think the time peroid is 180 days, but I'm not certian, so don't quote me on that.