Genetic Resource International has a few beef bulls available. I don't know the exact price of the semen, but I thinksemen will cost about $50-100 more than a unsorted straw from the bull in question. More information on cost may be available from companies that have sorted sperm for sale.
Conception rates in beef cattle appear to be similar, roughly 10% lower as compared to unsexed semen. However, the trade off is about 90% sex selection accuracy.
I think application of this technology on a beef operation depends on the operation. If you have a HUGE price advantage for producing one sex versus the other, it may be worth it. But for most general commercial beef producers, the cost is probably prohibitive, at least for now.
For my money, I would only use it on elite embryo donor cows where bulls or heifers from that bloodline are worth a lot or if I was producing embryos in an incubator, where I could fertilize hundreds of eggs with one straw of semen. One other thing to keep in mind is that the sexed straws are packaged at lower concentrations than unsexed straws, so that may affect how it is used.
Josh