Based on my reading of several novels it is clear that beauty standard in the 6th world is very much like what we have in the real world. Any kind of race mix can happen, but in general our(western world) standards survived the awakening.
Elves are considered the most beautiful and some of the other metatypes less so. This can also be seen in the charisma stats listed in the character design section of the RPG books. Statistically, elves have a higher chance of being beautiful then any other race, but beautiful people can be found in all races.
Everyone can't date an elf however and metahumans often go for someone their own race. This is also affected by the fact that metahumans form societies based on race and (sub)culture. If you live in a dwarfen suburb/ghetto/cave there is a greater chance you will find a partner that is dwarven than something else. But you will still stop to look at the posters with the impossibly beautiful elves on it.