Medical Progress
Vitamin D Deficiency
Michael F. Holick, M.D., Ph.D.
The full text of the paper is online and while mainly about the need for adequate vitamin d status there is a section on acquiring Vitamin d from sunbeds.
in particlar "For patients with fat malabsorption, exposure to a tanning bed for 30 to 50% of the time recommended for tanning (with sunscreen on the face) is an excellent means of treating and preventing vitamin D deficiency.
Also worth noting "Tanners had robust levels of 25-hydroxyvitamin D (approximately 45 ng per milliliter [112 nmol per liter]) at the end of the winter and higher bone density as compared with nontanners (with levels of approximately 18 ng per milliliter [45 nmol per liter]).