I wouldn't suggest it for polypro.. If you want a lighter hoop but still want a big diameter go with hdpe. Practice with a hdpe hoop till your ready to downsize. I sell polypro hoops and making them over 36''' they get really wonky. There are sellers on etsy (I'm one of them) that will sell you a 40-42'' polypro hoop that size but will charge you extra since they are using a lot of tubing to make the hoop.
Also don't worry about jumping to a polypro hoop just because it's the next big thing and everyone else has/wants one, take your time downsizing in diameter and tubing. You don't want to buy a hoop thats so light that it slows your learning process. I've sold a couple of hoops that people then say it's too light and have trouble learning new tricks with.
Its a white tube similar to polypro but stiffer that allows to go bigger than 36 without having wonky hoops. Its also very responsive. You can find it at almost every online hoop store and on etsy.
Martka sells them: http://www.etsy.com/listing/64779866/blank-hdpe-hula-hoop?ref=sr_li...
I make polypro in Canada, where you are (I'm in Vancouver) and can make it in whatever size you want. I have color too!!!
If you're in Canada I'm Superhooper's Canadian distributor (shipping is way less within Canada) and I'll likely be in Victoria towards the end of July for the Electronic Music fest!