CAD for PC builders

I was on pcpartpicker one day putting together a dream build (link:http://pcpartpicker.com/user/hhamama66/saved/7cGYcf). Now I have two open air GPUs and as we all know, in SLI there is a possibility that the bottom card will throw hot air on the top card. So I decided to look for a solution. As I was snooping around Corsair's website one day, I noticed that they had the HG10 liquid cooling bracket that would allow folks to conveniently liquid cool their GPUs with one of Corsair's hydro series AIOs. Now, in the build, I put both an h80i and an h100i as well as a ax860i 80+ platinum PSU that is slightly larger than standard atx.

Here's the part where I pitch in my idea, since I can't tell wether or not he tubing on those coolers would be long enough to reach a GPU mounted towards the bottom of the motherboard, wouldn't it be nice if we had a CAD program for PC builders? Something where we can put parts together and see wether or not they'd interfere and wether something will end up aesthetically pleasing the buyer.

In my situation for example, I would want to know if the h100i's tubing would be able to reach the card that would be placed at the bottom or wether or not I'd have to place it at the front of the case or the bottom and if I put it at the bottom, would my PSU be so long that Cable management would be awkward?