I doubt you will find any "For Hire Helicopters" here in La$ Vega$. I think the only one that is cheap enough for training will be Silver State Helicopters. They have a website.
You may want to check with guys like NrFairy. I know he rented one in Southern California some years back. Others here also get block time somewhere in Southern California.
Getting a conversion is not as easy as you make it sound.....