Any chance there are any lakes/resorts in central Iowa?

Yes, there is a chance.

There are a few lakes in central Iowa. Clear Lake near Mason City, Iowa is one. It's location is north central Iowa. There are some other small ones-but not many. What location are you looking for?

Don't know if you'd call any of these "resorts" but there maybe bed and breakfasts or houses / condos that you could rent on some of these: Okaboji has condos to rent but it is not Central Iowa.

Lake Panorama - west of Des Moines, Iowa
Red Rock Lake - Pella, Knoxville area (east of DM
South of Des Moines down I-35 and then a bit west:
3 Mile Lake - Afton, Iowa
Sun Valley Lake - Ellston, Iowa

Lake Okaboji in NW, IA

Lake Rathbun-south central Iowa.

Why Iowa for lakes and not Minnesota?

Southern Missouri and Arkansas have several resort area built around lakes.

Lake Okoboji, this is really the best lake location in Iowa.