After much toil, I think the only way to do this is by creating an InfoPath-based content-type. You can create the form with whatever fields you like, and add whatever styles you like.
Now, to make it work, you have to make sure your certificate is installed in Central Administration > Security > Manage Trust. (See this thread)
Also, you have to upload a data connection file. First, create a
Data Connections library somewhere in your portal. Then, in InfoPath, you have to go to (in the ribbon) Data > Data Connections, and, having selected your data connection(you know, when you told it whence to upload the submitted forms), click on "Convert to Connection File". It will prompt you for a url with a file name. You should specify the url to your data connection library that you just created in your sharepoint portal, and give it a file name with the extension .udcx - something like this: http://myportal.mydomain.com/dataconnectionlibrary/myDataconnection.udcx
After that is done, you can go into your forms library and add the new content-type, complete with all your nice formatting. If you want to display the form's fields and values like a regular list instead of like a document library, you have to create a new "standard" view.
Hope that helps someone!