And the plugin FileTransferPlus already supports this. You DO need to open the correct ports on your router and firewall, it won't open them itself (yet). And it's drag and drop compatible.
You drag the file to your messenger window, drop it, and the plugin will send your ip and other connection info to your contact in the window, after that both computers will start the transfer and use the max speed it can get.
To download the plugin and for more information about it go to the official filetransferplus help and support forums
www.filetransferplus.com