You probably can use tulle to imprint very thin fondant with probably some gumpaste to keep the shape you want.
If your looking for patterns the Wilton website has a lot of their patterns available in PDF format for free, its listed under the learn tab, pattern, then pattern locator. It will also depend on if you want the baby carriage to be 3D or flat? You could always do a buttercream transfer pattern onto a sheet cake for a flat pattern. To make a 3D version either fondant/gumpaste pieces or piped royal icing patterns put together to the baby carriage. Also, if you do search on their site it may be listed under baby buggy instead of carriage. Hope this helps. Good luck in your search.
Thank you so much for your fabulous ideas. You are both so helpful!!!