Conservatives in Massachusetts may well vote for Brown as the lesser of two evils. But I doubt very much that he will get a repeat of all those big donations from conservatives all over the country next time.
The two main motivations—to take back the Kennedy seat and to elect a pickup-driving conservative—will no longer be there.
There will be other races and better candidates on whom people will prefer to spend their money, especially out-of-staters.
Why is Warren less conservative than Brown?