I think it's just a question of recognizing that there are lots of different body types and style preferences. For those of us who aren't very curvy, clothes cut specifically for women actually helps us look like, you know, women. Put me in a men's t-shirt and you can't tell I have any shape at all, so I avoid t-shirts cut for men if I can at all help it because I do like to look feminine.

Her Universe is a great site that caters specifically to girl geeks. It started as a Star Wars store (the founder is the voice actress for the Clone Wars cartoon character Asoka), but has been gradually expanding to other fandoms. She started it specifically as a response to this kind of thing, geeky sites that sell nothing for women.

Now, they've had their issues with recognizing bodies come in different shapes, too, not so much because they don't recognize girls can be geeks, too, since that's their specific mission, but with making clothes for women who aren't slender. But they're pretty responsive to suggestions. My more curvy geek friends have had good response when they've complained that just making a shirt bigger doesn't mean it will work for a bigger woman, and Ashley's been really trying to make changes along those lines as well.

If I had money for all the geeky clothes I wanted, that's probably where I'd spend it.

ETA: Also, they have this instead of this.