I have the HP Scanjet G4050 photo scanner and it does 16 35mm slides at a time. Lists for $219 but you can find it on line for much less. Great product for photo, negative and slide digitizing.
I have about the same number of slides as you plus lots of photos and have gotten about half digitized so far. It is always a question of time to get it done. Since it will slow down your computer to store them there get a separate hard drive. I have a Terabyte hard drive that is great for storing large quantities of data like photos and slides.
http://h71016.www7.hp.com/dstore/Mid...piers/scanners