This is harder than it looks. We found one solid candidate on Wednesday, but it was way over budget and didn't look as amazing as its price would suggest.
On the bright side, this gave me an excuse to investigate almost every clothing store along Haji Lane. I was there around lunchtime on a weekday and was surprised at the number of casually-dressed shoppers who were also out and about at that time.
I'm tied up with Writers' Festival stuff this weekend, but the dress search will resume next week. If anyone has any suggestions, leave them in the comments? Everyone says Daniel Yam will have something, but that's been a bust so far.