FYI: The mechanism that gives the ability to limit output bdw is called in the community (IEEE, IETF, ...) "shaping". (I suggest to google it). This is one basic function in networking and telecom for bandwitdh provisioning.
Cisco call it rate limit, but they always change labels (HSRP, ...).

I don't know about linksys but I would be surprised that a so called router does not implement such a basic function.

Anyway, shaping the uplink bdw of your room mate would not be fair & is a first step to room war.

As you play with the beauty of linux (or on your linksys if it offers QoS), you could try CB-WFQ (Class based weitgh fair queuing mechanism) to set 2 priorities high for u low for your room mate, this would have the enjoyable result when congestion with minimum latency and throughput garantee on your last mile connection.

If your studying networking such experimentation would be highly valuable for your technical background. I personnaly need to understand those functions for VPN and traffic engineering...