the glam photog's do the 'photo days' all the time with 3-5 models. I did the nude workshops for years before the internet got huge.
Paid the girls $150-250 for the day and the photogs paid me $250 for the day, usually 4-5 hours. Nude, spreads, etc. no wild stuff.
Check out
www.garageglamour.com to see how it's done...they've been at it for years