Jeff, it seems that any custom cabinet shop could very easily replace the cabinet doors for you. To see the process, check out this thread from Boy Wonder
You could also consider having the cabinet shop replace the SMB MDF panels with either plywood or solid wood doors to assure that they won't absorb water in the future. I'm in the process (slowly) of replacing all mine with solid hickory to give me a more rustic vibe.
Also, I'd be in the "camp" that says you should keep your van and upgrade the interior rather than getting a newer used version. As you said - the running gear is in excellent condition. Of course if your needs have changed and you want a different power plant or floor plan then by all means maybe moving on is what you should do.