Are there any alternatives to (dental) bite wings?

Not really: No... Bitewing x-rays are appropriate every 6 month to 1 year.

Very specific xray: The anwer is no, there isn't an alternative to bitewings which are specifically taken to diagnose decay between the teeth that the dentist can not see with the naked eye.

Yes and no: While a full set of bitewings will see through contacts all the way to the cuspid, it is now possible to take beautiful bw periapicals without the need of an intra-oral sensor or tabbed film. Companies like planmeca and sirona (others too) allow a robotic external arm to capture these very diagnostic images. I love mine, and we are not speaking of cbct here, just a "slice" from a specific part.

Working blind: Considering that bite-wings are considerably low dose, less radiation than a couple of hours in the sun, they are exceptionally safe. The information they supply is invaluable. Asking a health care practitioner to treat without benefit of imaging of anatomy that can't be seen with visual inspection alone is asking the practitioner to work blindfolded...it's unsaf3 and ineffective.