Does anyone know if variegated cactus can pass on the trait through seeds, even if it has to be pollinated by another variegated cactus?

Yes the trait can be passed on and generally the offspring will have varying degrees of variegation. This can differ from species to species but as a general rule the trait is passed on to some degree in the offspring.

It does not need both parents to be have the trait, one is enough to pass it on. I have had greater success (If only having one) when the variegated plant is the father.

Thanks, thats good to know. I've been working on getting a number of variegated cacti, for breeding and refining.

Yes, they do - sometimes.
An easy way to obtain variegated cacti is to sow japanese astrophytum cultivars.
Or you may cross pollinate some of your cacti - for example lobivia and chamaecereus.
Then sow the seeds and graft everything that looks differently or odd.
May be you get something like this:

The whole story (most of it in english):
http://www.teratopia.biz/chamaelobivia1.htm

That's pretty good, it has me thinking of new types of hybrids to try.

That is such a cool plant Torro !! Very cute.

I have 2 floweing size of varigated asterias (kabuto nishiki).
One is grafted and the other is own-rooted.
When you used a varigated plant as the father, you will get high percentage of varigated seedlings.

The photo is 1 year old asterias seedlings, sown seeds on 28th August 2010.
Since my target was red flower, I used varigated asterias as mother and red flowering asterias as father.
Around 30% of seedlings were varigated with various degrees of varigation.
I selected 25 seedlings for own-rooted plants and repotted last September.

I think 2 seedlings of right end on 3rd row from top are good degree of varigation for own-rooted plant.

Hanazono