Where can I find a suitable rear live axle that I can use on a custom-built car ? Also, what is the price range for a rear live axle ?

I thought of using a rear live axle from a Hyundai Starex but my officemate said that I should look for a live axle that is designed for high speed. I need a relatively long rear live axle, the ones I see in owner-type jeeps is short

According to Chassis Engineering (by Herb Adams), the chassis should be designed around the type of suspension that will be used. I can't start the ladder chassis design coz I don't have measurements of the rear live axle that I'm going to use

I know many will disagree with using a rear live axle but this is my first build and I want it to be less complex and less expensive

Thanks