I'm looking to get a 2008 Titan, and I wanted to tow a 2008 250Z and Corvette

I've done rough weight, and the Corv+350 is around 6650 LB's, and an open top trailer is around 3000LB's (Well thats my rough guess so far, I havn't found a website to verify weights)

Would the Titan be able to tow this? And does anyone know where I could get a custom trailer made in calgary/alberta ish area that is open trailer

Able to? Yes

Should you ever? Probably be okay if it was only occasionally.

Should you regularly? Absolutely not. If you are towing that much weight regularly, you need something more like this:

While the Titan is rated to tow over 9k lbs, it won't do it well. You're talking a serious load there that should be done with a 1 ton diesel. You'll cook the transmission and probably burn up the rear end fairly quickly in a Titan with this load - that's just well beyond what a 1/2 ton truck should handle.