You might be able to add a board above your trim, the thickness of it and the length of your blind and mount your blind to that! That's what we did--but, we also added a valance to hide the blinds when pulled up! Here's the Photoshop mock-up of the valance idea before I actually made them. I wish I had a pic. of how the blinds were mounted before!!

I don't know of any in vinyl except in the patio doors.

Mie0782, what’s the advantage of a slider over an awning? Or were you thinking vinyl vs. fiberglass? We installed vinyl about 15 years ago and they have performed well, but now that we’re changing out windows with this remodel, I want to upgrade them. I’m also more concerned about environmal toxins today, so I’m trying to avoid vinyl if I can (creates toxins during manufacturing and also if the house catches on fire. i live in CA and though my town isn’t considered high risk, the last few years have seen unprecedented wildfires so you never know. Even if I’m not exposed to the chemicals personally, I’d rather avoid putting them into the environment if I can).

I have inside mount for my casement windows with blinds. You can change out the handles to either one that folds or a smaller one that looks like a T. I don't know if you can use them on all brands of windows so this is probably something you would want to check out if you are interested. If you know your window brand, I'm thinking their web-site will offer several different handle options. Though more than likely you can find them elsewhere, too.