Everyone I've talked to that's tried clipless has raved on and on about it and refuses to go back to cages/straps. Instead of throwing down $80+ for double cages/straps, I've been toying around with the idea of riding clipless around the city with some MacGyver'ed street shoes. Obviously, they wouldn't be as good as riding with shoes made specifically for this purpose, but this would let me get around to classes and errand runs while being able to wear normal looking shoes. I did some Googling and came up with this:
It seems that all the person did was drill some holes and bolt in some cleats. The bolts can be covered up with Superfeet or another shoe insert. This would probably greatly reduce shoe life, but I think this can be prevented by protecting the drilled areas with eyelets.
I was thinking that if this were to be done, the shoe would need to have a thicker/stiffer sole (Mexico 66's are pretty thin), but this seems like a very legitimate way to have normal looking shoes for everyday use and rides under 15 miles. There's even the possibility of Dremeling out part of the sole so that the cleat can be slightly recessed.