I love Jude Deveraux's books, too. Here are some romance and romantic suspense authors that I think are pretty good matches for Jude Deveraux (and whose works I also love):
-Julie Garwood (I've enjoyed every one of hers that I've read like Prince Charming, Saving Grace, Guardian Angel and many more)
-Linda Howard (I enjoy her books, too, especially the romantic suspense like Dream Man, Kill and Tell, Dying to Please and many more)
-Catherine Coulter (I really love most of her books. Some books I really like are the FBI mystery series starting with The Cove, The Sherbrook Bride series starting with the book by that title, The Duke, Lord Harry and many more.)
-Johanna Lindsey (I really loved her two-part series Man of My Dreams and Love Me Forever. I also enjoyed Until Forever - a time travel romance - and The Malory family series, and the Medieval series which includes Fires of Winter, Hearts Aflame, and Surrender My Love.)
-Amanda Quick (This is the pen name for Jayne Ann Krentz...these books are mostly Regency period with some set in Medieval times. Among the books I've really enjoyed are: Wicked Widow, Slightly Shady, Don't Look Back, I Thee Wed and many more.)
I also really enjoyed Mary Jo Putney's books, Loretta Chase, Jo Beverley, Mary Balogh, Lynn Kurland, Nora Roberts, Jayne Ann Krentz, Elaine Coffman, Meagan McKinney, Christina Skye, Catherine Anderson and many others.