By now we should be able to change the color of a grayscale PSD (WITH a transparent background) placed in Illustrator. This is doable with placed PNGs but only when applying Adobe/Spot colors. With PNGs it’s not easy to edit these images in Photoshop (the way you can with a layered PSD). I love being able change the color of my linked PSDs on the fly along with my type so that I can quickly audition colors in Illustrator. But I can only do that with a non-transparent PSD, so my workaround has been to copy the color I want from illustrator, paste it into PS and create a color overlay of that color, so that when I save out the PSD the color is reflected in linked image in the Ai file. Anyone know of a ticket to request this feature?