Being a grown up- Credit

Ok. We applied for a credit card and were denied. Before everyone goes and jumps on us about applying for a credit card let me tell you a little bit about our long hard decision and why we came to the conclusion to apply for a credit card.
We need to build credit SLOWLY! In about 6 years Josh will be graduated from school and we will most likely be looking to buy a house. My dad has raised me well and I believe renting is about the worst waste of money. I would rather put our money away into a home. So I know the minute we find somewhere where we will be settled for years we will be buying a home. Neither me or Josh have ANY credit. We have never taken out loans, or had credit cards. Long story short, we don't want to end up 6 years down the road looking to buy a house and have to wait 2 years to buy one because we have to quickly build up our credit. I would rather put 1 tank of gas on our credit card each month for the next 6 years and have credit by the time we are ready to purchase a home.
We are in the positive in our cash flow. This credit card will not be used to pull us by through the rest of the month to be paid off next month.
As far as I know, you basically can't get much in life without credit.
I really disagree with the system. You would think you should be praised by banks for not ever having to have a credit card or having a loan, right? Nope. It's frowned upon.

So here comes opinion time. How do we get our credit built up enough to be able to apply for a credit card? I already checked with our landlords and they don't do anything to work rental payments in with credit companies. (I've heard that some landlords will). Soooo....what is a young couple to do?
And we are not looking for the answer "You should never have a credit card and find a way to build credit another way." We have done our research for months, talked to multiple people, and realize that you can put yourself in a very bad situation with a credit card, but you can also put yourself in a very good situation with one.