While I am not a fan of bi-level counters (peninsula or island), I also don't like cooktops on islands for the very reasons you mentioned. But, I also don't know why the "ledge" has to be so big - couldn't you just make a ledge 4" high (good place to put outlets) and 4-6" deep (more like a "wall")? just to give you some separation?

I have a range in my island, which I love. We made a raised panel back piece that is trimmed out, but not a ledge. It is about 5-6" high and about 1.23" thick with a cap on top. It keeps people behind the island from accidentally touching the range top. And as you say, keeps things from falling off the back. If people are going to walk behind your island and that walkway is only 27", I think that it is critical to have a raised back - 27" seems much too tight to me.
Diane

I have a raised ledge behind my range, it is 8" high and 11" wide. Besides serving as a barrier to the adjacent dining area and walkway, it is a great usable landing space for staging plates to serve on, and also as a buffet for gatherings. I would not want a single level counter behind the cooktop area, unless it was two feet wide or more.

That's a good question sjhockeyfan. It's because we are using a design company that works with Ikea and the designer built the ledge out of cabinets. I am actually going to take your suggestion, power muffin, and ctycdm back to H and see what we come up with. It might be that a simple 2 inch ledge is all we need, to gain extra walking space behind it. All such great suggestions! Thank you so much

what if you got a downdraft vent that you put up while your cooking - it will stop the pots from sliding toward anyone sitting on the other side.

You've got bigger problems than the safety zone behind the cooktop. A 27'' aisle is a complete dysfunctional dealbreaker. Building codes usually specify 36'' as the minimum, and the NBA specifies. 42'' as the minimum. You need to reevaluate the design as a whole. I'd put the range on the back wall and add a prp sink to the island instead to take dvantage of that 70% of the time spent in the kitchen doing prep. And the island needs to be much skinnier on he one end to get you the acceptable aisle.

This post was edited by hollysprings on Tue, Aug 12, 14 at 21:29

housebuilder14, we thought about that, but I read up on the downdraft, and many people here, and on chow.com, really don't like them. H also didn't like that we would lose the space underneath. One of the main reasons for the remodel is that my kitchen has 2 cabinets; one under the sink and the other to the right of the fridge, so we are filling the new kitchen and dining with cabinets.
Thank you hollysprings; you are correct if the 27" was a wall that would be really tight. It's actually the measurement from the edge of the new island to the edge of the pantry (which is actually an old coat closet, I think) Behind the coat closet it's 15 feet to the wall of the living room. The closest thing to the edge of the new island will be the edge of the couch 8 feet away. My poor little house is only about 950 sq. ft, 1 bath/2 bed, so everything in here is tight.
Thank you all so much for your insight, we really appreciate it. :)