Create a custom HTML widget

I would like the ability to replace the catalog with a custom HTML widget that links out to our catalog. We cannot use the catalog software (we are in a library consortium and share a catalog with three other institutions), but I would still like to be able to create a library presence in Populi. You can see an example of this in action at our library website: http://library.ocom.edu/. The catalog search bar links out to our catalog, which is stored on a different institution's server.