There aren't many 180mm gyuto profile knives out there. Not a popular size really.
Are you looking for a knuckle clearance knife? When you say "utility" I think more of a petty.
Here are the search results for a 180mm gyuto:http://www.chefknivestogo.com/nsearch.h ... 80mm+gyuto
and for the 180mm petty's:http://www.chefknivestogo.com/nsearch.h ... 80mm+petty
In the petty's there are some great knives. The HD from Kono, Richmond Laser, etc.
However, I will caution you on one aspect. A 180mm wa-petty is kind of close in length to a 150mm western petty. So if you have a 6" (150") western handled sandwich/petty/utility knife.....I might suggest getting a 210mm wa-petty. I have that knife style and love it....use it all the time.http://www.chefknivestogo.com/nsearch.h ... 80mm+petty
Another option is to look at a 180mm santoku, if you're looking for more of a gyuto style knife with knuckle clearance.http://www.chefknivestogo.com/nsearch.h ... 80mm+petty
Lots of good options in both categories.