You can send and receive unsupported files via iMessage with SendAny and ReceiveAny. SendAny will allow you to send files to iMessage from iFile, DropBox also filesystem. Not only that, there is multiple files sending ability too that allow you to send multiple files as a Zip file or folders as a Zip.
And if your iOS devices or OS X beta have ReciveAny installed then you are able to receive files, like receive Microsoft Office document, iWork documents, PDF, RTF documents, also CSV file and Text files.
If you are interested with these tweaks, you can grab SendAny for $1.99 and ReceiveAny for free. They can be found under BigBoss repository for you to get and install them for your jailbroken iOs devices.
Hope this post helps you.
And see you again in another posts.