Hee hee. But from what I understand, the Mark goes away until Voldy calls them. That leaves some wiggle room. :)
BTW, I am not 100% on Malfoy working at the Ministry. I just got that from Chamber of Secrets (the movie, that is) when the Malfoys and the Weasly's have that showdown in Flourish and Blotts! :)
I am quite likely wrong, since now that you mention it, I don't recall JK mentioning a job for him at all, other than being a school governor. That line from the movie "See you at work" is probably just a throwaway line, anyway.
Come to think of it, in the earlier books I thought it mentioned that he works there, but in OoTP everyone was upset because he was seen there. Hmmm.