If you’re willing to do half the work (cutting)…you can ship the pieces off to Ticche & Bea and have it sewn for you, obviously this is much cheaper. They also sell kits for doing it completely yourself.
If you want to include little booties or items that are bigger, just get a collage/display frame…you could even include special items, such as: hospital bracelet, jewelry, copy of birth certificate, foot prints, a rattle, picture of child in that outfit, etc.
The best way to store clothing is to first launder the items then wrap them in acid-free tissue paper. This prevents them from changing color or turning yellow over the years. Place them in a tightly sealed box (not cardboard) and store them in a cool, dry, and dark place.