Some of the better high power USB adapters have dual USB connectors.
The Engenius EUB9603h has dual USB plugs and 600mW of transmit power. Keenan Systems Wireless Store - EnGenius 2000mW EIRP EUB9603h 802.11bgn USB adapter
In reality its more the chipset and recieve sensitivity that gives these the great range.
They are much much better than built in WiFi and really help boaters, campers etc get a connection where they otherwise could not.