Perhaps you're upgrading to a newer iPad and you really like your case, or you want to adapt a cheap 1st-generation iPad case to your Android tablet. Either way, you can easily add camera and port access holes when needed by using a small precision drill.
Design weblog Apartment Therapy points out that the old adage "measure twice, cut once" applies here. You'll want to measure where you need to make a hole for your camera or headphone jack, draw the hole on the case, and drill the hole. Trim around the hole with a small pair of scissors for a neater finish.
Hacking a 1st Gen Case for a New iPad [Apartment Therapy]