Does anyone know if its possible to upgrade from CUCMBE to CUCM (running on a 7828), is it possible to transfer DLU's from CUCMBE (7828) to CUCM (7825) if the CUCMBE is being traded in, and if there's a tool like DMA to pull the configuration off the CUCMBE and onto the CUCM? Thank you in advance!
The MCS7828 can be reused when moving to a standard UCM cluster. See footnote three on the restriction (namely UCM 7.0 only).
You cannot however migrate the database over. The schema on UCMBE includes Unity Connections data and other customizations to allow them to play together. You will need to configure a new cluster.
This is documented here for reference:
My recommendation would be purchase a second MCS7825 (or 7835 depending on your requirements) and configure that as your first node. You can then migrate things to it and add the 7828 as a secondary node - after a fresh install - once you are up and running.
Note you would also need to buy an appropriately sized server for Unity Connections.