D.I.Y. Crossover Adapter

Hello Experts,

I know I can buy crossover adapters online, but I need one now, and cannot find anyone in the area which sells one.  I've looked a little into making my own by using a coupler and a crossover cable like so:

-rentonc:
"you need a straight through coupler(I have not seen a crossover version anywhere) then you plug a short crossover rj45 cable into one end.
What you end up with is the tool that you want
When this configuration is plugged into any normal straight through rj45 cable it effectively creates one long cross over cable.  "

But another expert (RobWill) States that such an adapter would cause too much interference and greatly degrade the quality of the cable. If I made an adapter like this, would the signal  be strong enough to link 2 XBOXes over an approx. 75 foot length of cable?

I need this adapter so that I can change between using a switch for multiple XBOXes to using a crossover cable for two XBOXes.  A switch is better than a hub in this situation correct?

Also, would a crossover adapter convert a crossover cable into normal ethernet cable? If so, I figured that this would be optimal since a single crossover cable is what I will be using most.