Well, as you know my models are not yet complete, lacking the cross head pump and a few other details. Disneyland was Walt's model railroad that would never be complete like my WDW locos and trains. Since this is a hobby, I have to keep my annual income from such projects below a threshold that would make the IRS think I was running a business.
That said, I may take on the task but I need to see what parts would be needed to build a second Lilly Belle so a good estimate of your cost can be made. I'll send a PM when I have a price, and with some travel coming up it may not be until late August.
I do have the Tyco base locomotive, I bought two extras for my project.