you can try moutning it on the dash with some sort of flip up thing like the one that comes with the gps. I just got one for my old honda accord but i dont know where im going to put it either. If you can fiberglass you could take out all the headunit and lcd screen in place, and custom mold a piece to hold your screen. Then you can put an aftermarker headunit in the glovebox
someone had the part number for the gps enclosure for mazda 3, give em a call and get that for like 140 bucks (USD) , if u dont want that then i would suggest get those lil brackets its like a thin rod u mount somewhere and the lcd goes on top facing u.