Reply to my controller doesn't have enough buttons

I ran out of buttons to map on my bcd3000 so I am looking for a VERY cheap alternative to a midi controller. Has anyone used a controller + a numeric usb keypad at the same time with virtual dj? I know that if it works, it will work in parallel with my pc keyboard, but I'm curious if it will be able to be mapped like a keyboard. Any help?
Thanks for the help guys, once again this community is a wealth of knowledge.
Peace