I have been looking on the net trying to find suction cups with brackets for roof racks that you make with your own 2x4s. I need help. Thanks.
Yeah, that’s how I made my first racks
in 1973. At that time, suction cup parts were available everywhere. I have seen occasional adds for them in the little ads in the back of canoe mags.
One suggestion I would make is to use connecting struts between the front and rear crossbars. This will make for a more stable setup overall. And make sure you have a good place for the pull-down strap clips to grip above your doors.
If your car is not too snazzy, you can buy brackets from Yakima which bolt or screw through the roof sheet metal, allowing you to use rain gutter style racks. Often discussed, seldom done.
Suction cup feet
Should be available at any chain auto parts store, Sears, WalMart…
tried
I tried several auto parts stores. No go. I’ll give Wally a try.
I wonder
if something fell off a rack using suction cup feet and the resulting lawsuit caused them to cease to exist.
Another possible source
Search for McMaster-Carr’s website and, once there, do a search on suction cup. I don’t know if they carry them, but they do stock all kinds and sizes of doodads for making things, mostly metal doodads. Worth checking out, and their service is top-notch.
Piragis and at least one other catalog I saw recently list a suction-cup crossbar for sale. I thought it was expensive, but then again any rooftop rack (except HandiRack) is expensive.
tried that
I’ve tried the net and all of the sites listed here. None sell just the cupsa and bracket and the ones with the bar seem high as you said. I’ll give McMaster-Carr a look.
could be
Could be. I’ve looked in several places. I want one that I can bring a rope through the door for nearby sojourns and not spend much money. I don’t care for those that clip to non-gutter vehicles. I’ve got a rack I use on the car, but want one to use on a another vehicle without changing everything around. And, now it has become a quest. 
The old way seemed so much easier.
I got a set
From the canunut. the suction cup was shot so I went to Universal rubber in Denver NC and got something close. Instead of strapping on the assembley I drilled a hole through the flange around each door, and used an eye bolt so I could tighten each corner down or remove easily. Used that system for over a hundred and thirty thousand miles on my old Shadow. If I realized I was going to hang on to the car that long I would have just drilled throughthe roof like Canunut suggested.