I take bridesmaid dresses to Janette in Arlington. She is right on Mass. Ave, is visually similar to Eleni, but wears sexy shoes :) She knows the whole formal-dress drill (bust pads, a hem that won't trip you when you dance, etc.) and was far cheaper than other places I called.

Here's her info:

Janette Tailoring & Alteration
805 Massachusetts Ave, Arlington, MA 02476
(781) 646-8410

Also she's open after 5 and on Saturdays!