Alien Gear has shells (the Kydex part) for the 45. I bought an AG for my Glock 19 and a shell for the Shield 45. They swap out. They have screw adjustments and different standoffs to make the perfect fit. I used the AG for my Glock and made my own for the 45 shell.

What are you thinking for your first holster, In the waist, Out of the waist? I like OWB due to age and I don't want to buy bigger pants. I also use a Remora holster ($25ish) for IWB (no belt needed) and for storage.