Not in DC, but the Pentagon City RI is very convenient also.

Don't know if they have any room upgrades available at the Residence Inn Arlington Pentagon City, I can't even remember seeing any 2-bedroon suites bookable, but maybe there are some.

What I like about it -
It's less than a five minute walk to the Pentagon City metro station which takes you across the river to L'Enfant Plaza and other DC destinations in about 3 minutes. There's also a very good selection of shopping and restaurants (Fashion Center at Pentagon City mall included) within easy walking distance and abundant free street parking on weekends.