Hey hive mind!

I've been a regular blog reader and occasional commenter since nearly the beginning (mid 2011), but so far I've only browsed the forums and never posted. I assume this has been covered, but my normally productive searching skills have thus far failed, so I'm breaking my pattern as a lurker. Can someone please point me to a site/calculator that allows you to plug in all the important bits to evaluate different mortgages over, say, a 10 year time frame? I'm specifically trying to sort out which mortgage choice (between various interest rates, fixed vs ARM structures, down payment amounts, point options, etc.) would be most advantageous for net worth by the time I sell the house, assuming I'll only live there for X years (likely 7-10) and assuming I'll invest all the difference (pretty accurate for me). I'm not looking to compare renting vs buying - I'm trying to quantify and thereby minimize the losses that I predict throwing such a vast amount of money into a single piece of real estate (primary residence) will incur vs. my typical index fund investing. **As a broad/simplified example question: if I sell the house after 10 years, would I be better off with a lower interest rate 15 year fixed mortgage or a higher interest rate 30 year mortgage, assuming I invest the difference? I believe the answer to this one is the 30 year - but by how much?** This magical calculator that I believe exists would answer this question with numbers (assuming I provide lots of numerical input up front), and then by comparing different scenarios and mortgages, I'll feel better about making such a large decision.

Does this exist? Or am I pretending that something complicated can be simplified into a public calculator? Thanks in advance!