What did you pay to get that name? What a find!
My initial thoughts is low $xxx,xxx... obviously that'd go to an end user. I think you're right to hold off for what you see as the "right" offer. It costs you just $10/year to do, and could earn you thousands! For every $xx,xxx offer that you pass on, you'll receive another in a few months. Eventually the "right" offer will come, so continue to hold off.
I think if Mercedes will pay $25k for bluetrac.com, i4.com is worth at least 6 times that. My valuation: $150,000+. I've seen worse domains go for much higher. In the right auction (like T.R.A.F.F.I.C. a few weeks back), this could get as high as $500,000 - $1,000,000... though that'd be a fairy-tale sale - possible, but not something to expect to come true.
Pavel